I can't say I have definitive data on that but when I look at the front page which includes everything that is federated by lemm.ee, I see tankie posts often and people are mostly in agreement. Something like this I would call tankie, and I see one of those everyday, maybe every two days.

I'm not saying that anti capitalist things are extreme on their own. But when it's mixed with the tolerance of overtly extreme memes makes you extreme. I'll ask again, what if it was the case for a right wing ideology? What if that meme said something like "But Zoe, the Jews are taking all the wealth and will not stop voluntarily." Would the existence of that hypothetical meme not make that community extremist? If it was just that meme on its own then fuck it, it's just edgy shock value stuff. But when the community is always slanting on one side, the meme has a more serious connotation.