Because it’s all politics. There is money in ridiculing a politician, rigtfully or not. Also, people don’t do that shit “organically”, it’s too much effort and has to start somewhere. So either it is 100s of accounts that were started by few people (bots), or it is specifically targetted by political opponents (bots).

Also, ask yourself, would you change your account name, set your avatar to that picture, just for a passing meme joke on a single video? No? Then why would anyone else do that?