Consider this perspective instead: ironic memes, or jokes, are often made in mockery of the thing or person they are being ironic about, such as "Hitler Reacts" video memes. People making them are not any likely to be antisemitic just because they enjoy the meme. Or how about all those lazy-as-fuck Trump memes Twitter churns out every week..? A lot of the people making them are openly anti-Trump, not pro.
Take Danny from the Game Grumps, for example.
He has grown so comfortable with his situation and being Jewish in an internet environment that he basically became immune to any negative effects and just rolls with it now, with this video being a giant compilation of ironic Jew jokes. And this video is from 2013, so you can bet your ass he did many more of these since then.
Ethan Klein from h3h3 is on a similar boat too, ocassionally joking about it and looking down on people trying to say he should feel more oppressed for being Jewish, as he fiercely opposes the rise of PC culture. Naturally, this means he is OK with the more ironic spins of Jewish memes, since those are normally the opposite of PC.
So, I understand your point and it is not a bad one, but it really comes down to perspective at the end of the day. I myself am from Latin America, and millions of people over the world would treat me like an endangered panda cub based solely on that because of our rough history with white colonization centuries ago… or do the opposite and say that my existence alone is why USA needs the wall. And you know what..? I care about neither of those people, nor any memes that spawn from any of these opinions. At the end of the day, I am just happy to live in an age where neither of these groups of people get gunned down for having such opinions or making memes about it. And yes, jokes and memes about colonizers coming in and killing, raping and pillaging have been a thing for decades here. We have some loved popular local comedians who have done so. Everyone is OK with it.