Comedians often feature holocaust jokes and whatnot. Jimmy Car in the UK does it quite frequently, presumably a few others, I don't watch much stand up.
It's not illegal (racism and prejudice is illegal in the UK) and I think most people see these jokes as harmless. But I don't get it, his 'joke', just said 'death to all jews', and other nonsense, it's not even a joke. There's no punchline there, it's just offensive.
The difference is that Jimmy makes these jokes with acknowledgement of the tragedy that the Jewish people faces, he never once jokes about anything that could be construed as he himself, hating Jewish people. He trivialises tragedy but doesn't express any hate.
It's a bit weird where people draw the line really, but PewDiePie's remarks are really weird here. Why would he show this content on his channel? Whichever way you spin what he featured on his channel, it's obvious anti-semnitism, it's not a joke, and in the UK at least it would be against the law.