If you say to a Jew, “It wasn’t 6,000,000, it was 600,000,” and you say it to a Jew who actually lost family, the emotional reaction is “Are you saying my brother did not die at Auschwitz?” Also, “deniers” of the ilk who assert that well, yes, 6,000,000 Jews died, but there was no “Final Solution,” most people did not die in gas chambers, they died of typhus or exhaustion or something, it matters not a bit to a Jew. My aunt’s brothers are just as dead and lost in a mass grave (or a crematorium) whether they died in a gas chamber or of a disease. Ditto for Anne Frank.
Also, there are the survivors to consider. They suffered, and often were affected for the rest of their lives. My aunt’s father was given milk to drink as the first food he had after his camp was liberated. It made him so sick, he could never drink milk again for years, and could not eat and dairy at all even for several years. One of his daughters was a hidden child, so while she was safe, she was traumatized emotionally, and it probably is at the root of her failed marriage. I think she had PTSD, because she was, from her perspective, abandoned by her family, and it was more than a decade before she could begin to understand why. She also was inducted into Christianity, and had to learn to be Jewish again, and never really had the comfort of Judaism that her siblings did.
My aunt has been disabled to various degrees-- she’s always had at the least a slight limp, and now she has had part of one leg amputated-- she gets along well with a prosthesis, but it didn’t have to happen. It’s the result of the malnutrition of being in hiding as a very small child. When she was in elementary school, she wore a brace that made people think she had survived polio.
Her oldest sister was in Belsen, and survived because she was pretty and blonde. She looked Germanic, even if she was Jewish, and she was part of what was named, post hoc, the “Joy Division,” women prisoners kept for the use and “pleasure” of the guards and occasionally visiting soldiers. It’s probably why she survived, though, because such women got better food, clothes without lice, and weekly hot showers. She also got very light duties around the camp, compared to being worked to death as the men and other women were. She also got pregnant. The baby didn’t make it, but it was a boy. So she can’t marry a cohen, and her first born son in marriage won’t count as her first born son (her first born child in marriage managed to be a girl, so, no worries there, though).
Imagine saying “I’ve just discovered that spousal abuse doesn’t really happen-- it’s all just misunderstandings.” You have invalidated the traumatic, and often defining experiences of many women’s lives, and have called into question the work of people who put in 50 hour weeks running shelters to help these women, and lawyers doing their pro-bono work on these cases. It’s cruel. That’s what it’s like. It’s cruel to call into question what we know to be true about the Holocaust.
I am as lost as you on denial by neo-Nazis. They hate us, and you’d think they’d be proud of the “work” the real Nazis did. There’s even an episode of the TV show Quincy that addresses this. Some young neo-Nazi gets what for from an actual former Nazi who is proud of what he did, and it turns the young guy around (it’s not the only thing-- actually meeting and knowing some Jewish people, and of course, some Quincy magic are also necessary). It’s one of the better episodes from the “message” stage of the show, when it stopped being about a coroner solving murder mysteries, and started being a “crusade of the week” show.
Let me add, though you didn’t ask, that I am against censorship, and I think people have the right to hate us. They don’t have the right to hurt us, though. There is a big, fat, visible-from-space line between the two.