It looks to be a combination of right wing political commentators and a fringe anti-vax group.
https://www.forbes.com/sites/stevensalzberg/2021/08/30/no-iv... https://twitter.com/oneunderscore__/status/14310404563648102...
"Ridicule is man's most potent weapon. There is no defense. It is almost impossible to counterattack ridicule. Also it infuriates the opposition, who then react to your advantage."
"Pick the target, freeze it, personalize it, and polarize it."
You practically invent your own enemies to knock down.
Experts say one thing.
Another group says a different thing.
When people say that the other group is not acting rationally, they respond with your post and claim that the experts are being mean.
Ivermectin is only being treated like a tribalistic team sport by the people who aren't experts.