The next line is:

Applejack: Even supposin' you're right about the math, and how Aryans aren't the same thing as tall blonde people, it's still wrong to put people into camps.
Erich: Really? You know Equestria's done it, right?
Applejack: W-what?
Erich (biting): In the Civil War camps were filled with dying, sickly prisoners to the point they almost burst open. And during WWII all of the Japanese Equestrians were rounded up into prison camps of their own because of racial tension. Plenty of them were mistreated, but it's funny how no one thinks that the Equestrian political system is irredeemable because of it.
Applejack: I... I never thought about that. I heard something about it in school, but I just assumed-
Erich: That sometimes nasty things happen because of wars? Did you know that Pol Pot is estimated to have killed 8 million people?
Applejack (disbelieving): Who the hay was he?
Erich: A dictator in Cambodia. Mao killed just as many in China, easily, and the Soviet Union wasn't bloodless either. All of them did it using communism as a step up to power, and yet no one gets thrown out of a building for waving a hammer and sickle.
(Erich grabs Applejack's arms and looks into her eyes.)
Erich: Applejack, the death count has never decided what we think of a political system, not in all of history. Someone - someones - are making you think that way in this one special case. Just wipe away all of the fears, all of the gut reactions, and ask yourself: who would benefit from doing that?

Was I close?

Before I address that, here are six places Erich (or an attachment) was mistaken in the original text.

The claim that Anne Frank's diary is faked is one the Dutch government took the most careful, laborious pains to dismiss through empirical investigation. The paper in the original manuscript was printed between 1939 and 42, the handwriting matches all surviving samples of her writings in school, and the ink involves a heavier-than-modern iron content consistent with fountain pens of the time. The ballpoint-pen corrections argument was made in court in 1980, but when challenged, the defendants were unable to produce any such corrections; Otto Frank did in fact include changes in the manuscript (for instance, a section about menstruation was cut out in some editions), but these were made in pencil.

While different death estimates are being given as time goes on, it is not actually because the number of Jewish deaths is being adjusted upwards. It's factoring in groups like the Roma, Slavs, Poles, Soviet prisoners of war, Jehovah's Witnesses, political activists, gays and the disabled, many of which had their own symbols of persecution in camps, just like the Jewish star. Members of these non-Jewish groups have also given testimony about the atrocities committed in these camps, including French prisoner-of-war Andre Rogerie, who was shifted between seven camps and produced the earliest drawing of camp crematoria on record.

Outside of denial sites, there doesn't seem to be any evidence of a body called the Allied Committee of Inquiry existing in the first place, even leaving aside it being able to conclusively prove the universal use of torture to extract confessions - a feat nearly impossible even today - or its strange conviction that Jews especially should be held for purgery. There also doesn't seem to be strong evidence for the existence of anything called the Allied Military Police HQ, which makes some sense given that the Alliance was disestablished three years before the date given on the paper. Even assuming both did exist, and that they were competent to make these claims, none of the camps listed in the report shown are the ones Erich estimated ovens and death counts for to Applejack.

In that same vein, Erich stumbles in both his math and his analogy by comparing a crema to a baking oven. While the exact number of ovens may depend on the accounts being used, they did not have a universal capacity; what mattered were the number of "muffles", the chambers where actual incineration happened. The Bischoff letter lists 52 muffles in Auschwitz, and estimates that each could burn roughly four people an hour accounting for daily maintenance, leading to a little under five thousand deaths per day. The Soviets' estimate, which in Erich's defense truly may have been meant to defame their enemy, was actually only a quarter of that number.

Erich is also right to object to the idea that 40s technology could cremate a body in only 15 minutes and not a full hour, but this is another snag with his analogy; multiple bodies could be placed in a muffle at the same time, not like cakes which are baked one after another.

Additionally, Erich's example to Applejack assumes that Jews were only killed in ovens, when many died of gunshots, starvation, thirst, typhus, dysentery, other disease, hypothermia, accumulated injuries, trauma, et cetera. The six million estimate comes from Eichmann's mouth, not the survivors', and a full sixth of that can be attributed pretty neatly to the Einsatzgruppen via 194 of their reports of Jewish extermination. The more of these peripheral atrocities you include, the harder it is to find the final number unrealistic.

Now:

Let's assume there are good rebuttals for every one of these points - not only that Frank is a hoax, but that Frankl, Wiesel and all the rest are just as fraudulent, that stricter standards should be used to estimate death here than in any other historical conflict, that all gassings are provably lies, that an entire country employing people specifically for the task could not handle the disposal of three thousand bodies a day even though that's roughly its daily death toll today. For the sake of argument, I will grant every premise Erich has so far put forward, as well as the forthcoming claim about the true meaning of Aryanism I've skipped over for time. He still gets nowhere.

If the Holocaust never happened, Adolf Hitler would have wished for it, just as he wished for it in Mein Kampf and on the Reichstag. Whether the party's eugenic utopia were to be achieved by a small amount of death or a large one, or merely by uprooting the European Jewry from their homes and deporting them en masse (a defense which only sounds reasonable because genocide is the first solution out of the door), it is still a wrong means sustained by equally wrong intentions. Nazism, like any extreme nationalism, requires a set of enemies with which it can scrub away the perceived impurities of its citizenry. Moreover, given everything about psychology we learned in the immediate post-War period thanks to things like the Milgram experiment, the idea that widespread atrocity was uncommon in that situation is almost laughable.

Erich also has yet to explain precisely what it is Jews are doing. He doesn't seem to believe that their trickery is genetic, and seems to want their religion and culture reformed somehow. This strikes me as the eternal curse of the Pharisee in a Christianized West. It's why Hitler's first treaty was with the Catholic church, why people blamed sickness on Jews infecting their wells in the Dark Ages, why the The Protocols of the Elders of Zion was fabricated, and one reason ISIS continues to crusade against the entire Western world. If the Holocaust had happened, as sad as Erich might be over their human suffering, wouldn't he find in it a bittersweet victory?

Again, keep discarding these issues onto the pile and the road gets no shorter. There's still a matter of why National Socialism should be used as a political system above any other. Taking the greatest hand-picked achievements listed by the Cascadian Nationalist Resistance, we certainly don't find very much. "0% national unemployment" is a bad joke; unemployment and homelessness were grounds to be put into camps, not to mention the war footing. Past that, anti-smoking regulations and national vivisection bans are just a matter of dictating personal preference to the masses in typical fascist style, and that highway system burnt itself out like all the rest of Hitler's resources as the war wound down. These are very basic, easily anticipated problems that jump up when things rest on a single point of failure, a defining trait of one-party-state fascism.

Once you take out all of the things that would get a reaction from anyone, National Socialism is nothing more than socialism without other countries, and flawed on those grounds as any other slightly non-vanilla flavor of socialism. Once the audacity of pointing to its few successes wears off on the listener, they can see pretty quickly why subsuming individual will for the good of the state is not a great idea even if it did give you great highways and perfect children.

Now, look how far down we are. We've climbed down a great big well, all the way to the bottom. Look up and you can see all the points this could've ended, all those bits cast off to push us a little further. They float like dust motes in lazy concentric circles, flickering long shadows against us here where our shoes are rotting in the groundwater. This is as far down as I can go, as elastic as I can make myself.

I went to the Holocaust Museum once. There was a large quote on the front, easy to miss because the font looked like a New York Times review out over the waterfront and you could just barely make out the Lincoln Memorial on the mid-horizon. But I remembered it, on this trip, and it took some real digging to find, but here's a more complete version.

"I visited every nook and cranny of the camp because I felt it my duty to be in a position from then on to testify at first hand about these things in case there ever grew up at home the belief or assumption that “the stories of Nazi brutality were just propaganda.” ...I sent communications to both Washington and London, urging the two governments to send instantly to Germany a random group of newspaper editors and representative groups from the national legislatures. I felt that the evidence should be immediately placed before the American and British publics in a fashion that would leave no room for cynical doubt. ... This is documentary evidence of sheer mass murder – murder that will blacken the name of Germany for the rest of recorded history."
?-Dwight D. Eisenhower