Something like 3 merlinis was funny the first time, specifically because the 3 of them (Merlini, Blitz, Winter) didn't actually look anything alike. It was sort of a more meta "We're poking fun at the 'all asians are alike' stereotype by specifically bringing attention to these 3 asian males who look nothing alike". It got played out real quick and then sort of became the very thing it was mocking, but at least it seemed like it had a point at the beginning. It was still racial humor, but it wasn't aimed at disparaging the people of their race, but more joke about the people who "do" share sentiments like that.
But yeah, stuff like "The joke is he's a jew" is just lazy racial humor from a shitty community.