In what way is it antisemitic?

If anything, it’s erasure of the non-Jewish victims of the holocaust.

(Probably) No, it isn't.

I want to be clear that it matters whether you were actually talking about the Holocaust. If you were using this as an analogy, about anything less traumatic than the actual Holocaust under Nazi Germany, then I would argue that it is anti-semitic, because it belittles the degree of horror that occurred. Don't compare other things to the Holocaust, that's shitty.

The following assumes you were actually talking about the Holocaust (EDIT: or something equally bad):

Does it erase Jewish culture, history, or trauma? No, it's clearly doing the opposite of that: affirming the trauma.

Does it dehumanize Jews? No. It's neutral to the humanity of Jews, except insofar as it's clearly meant to affirm the horrors of the Holocaust, which dehumanized and destroyed Jews and Jewish culture.

Does it perpetuate a harmful stereotype? Nope! It might be considered a stereotype that Jews know Hebrew, but it's not a harmful one, and it doesn't make the claim that all Jews know Hebrew in any case. In fact, it strikes back at the idea that specific facts about Jews are even relevant to the conversation about the Holocaust.

Most likely--if you were in fact actually talking about the Holocaust--the person you were arguing with just wanted you to go away, and gave you a bad faith rebuttal.

Edit to add: OP added context, and this conversation was about the Uyghur genocide. Clearly, the intention here was not to belittle the horrors of genocide, since it's actually a conversation about genocide. Not anti-semitic.

That whole comment chain is a trainwreck filled with assumers, "ackshyually"-vomiting users, and frankly I wish that I didn't read it.

That said: no, you were not being antisemitic. In that context, by "don't need to know Hebrew to know the Holocaust was bad", you're affirming that the Holocaust was bad, regardless of circumstantial knowledge that you may or may not have (such as knowing Hebrew). The opposite discourse (implying that the holocaust was not a big deal, or that it was good) would be antisemitism.

The other user's "ackshyually, Jewish ppl speak lotsa langs!" is correct, but contextually irrelevant. I simply fail to see how associating Hebrew with Jewish people would somehow denigrate them, even if they speak a multitude of languages. The other user is being at the very least disingenuous, if not worse (stupid).

I've always used "You don't need to know how to fly a plane to know when a pilot is bad". I don't think the saying you posted is antisemitic though.

No. It's a fact. You also don't need to know any other specific language in order to know that the Holocaust was bad.

No. Also "hell no". Don't argue with idiots, they'll drag you down to their level and beat you with experience.

I don't know why I'm investing any time into what sounds like an unproductive conversation, but maybe the objection was to the assumption that all Jews know Hebrew (and associating Jews with Hebrew and vice-versa)

It would depend entirely on the context.

I certainly don't know Hebrew and I know a lot about the Holocaust.

No.

It's people from Hexbear... From what I've seen, you can't expect anything other than this from them. Just don't engage them.

If they think that the holocaust was in any means okay, they're the antisemite (+ spitting on several more minorities the nazis tried to get rid of).

It isn't and that guy is pretty dumb.

It's antisemitic because it only considers the Jews and not the other ethnic groups killed? Even though the Jews were the biggest group? 🙄

Antisemitism is hostility to, prejudice towards, or discrimination against Jews. A person who holds such positions is called an antisemite. Antisemitism is a form of racism. Antisemitism has historically been manifested in many ways, ranging from expressions of hatred of or discrimination against individual Jews to organized pogroms by mobs, police forces, or genocide. Although the term did not come into common usage until the 19th century, it is also applied to previous and later anti-Jewish incidents.

Maybe to the Samaritans?

I don't think it is, but I would ask a Jewish person to make sure. Where is Jonah Hill when you need him!?!?

Oh, he just went to go get some milk, he should be back quick.

"Damn those antisemitisms and their looks at note and raises eyebrow ... acknowledged of the evils of Nazi Germany?"