You're referring to https://news.ycombinator.com/item?id=41066729. That comment was rightly flagkilled by users, but I believe you misread it. It was sarcastic and meant the opposite of what it appeared to be saying. In other words, it was more or less agreeing with your own view.

HN does get some genuinely antisemitic comments, most of which get posted by one or two serial trolls who keep making new accounts. We ban those whenever we see their latest incarnations—it's a whack-a-mole thing.

Edit: please see https://news.ycombinator.com/item?id=41071782 and https://news.ycombinator.com/item?id=41071809 also. I've replied in each place you posted this because people often jump to wrong conclusions about the community and it's important not to do that.