Isn't this true of any service, at least of a certain size? My Twitter feed is tightly, tightly curated, and even the comment replies to these extremely high-quality accounts are full of unbelievable levels of stupidity and hostility.

I closed my Reddit account after the last Danish parliment election, when it became clear that only left wing politic was considered “correct” and apparently any liberal party or candidate is not to be trusted, so no argumentation would considered valid.