Reddit is great for watching communities being radicalized. Wehther they do it themselves or they get a psyops push is up to everyone's guess but I've watched it several times.

SRS: Started out as a community pointing out misoginy and racism, ended up as a very weird hate group. I didn't watch it that closely, only saw the result.

some tumbler centered sub i followed, I forgot the name: same story, started quite light hearted, making fun of stupid shit said by kids on tumbler, turned into a right wing hategroup. This one I witnessed. They ran out of material quick, started posting lame shit but now they gave it their own, made up context in the comments. After a while, people who pointed out obvious satire got downvoted.