I'm not going to blame those nasty subreddits on the left; I'm going to blame those & all other nasty subreddits on the general nastiness of people, no matter what their philosophy or politics.
"Anti-conservative hatred" as equivalent is ridiculous on its face and whatever "misandry" the SRS guys promote should probably be understood in a context where there is no country on Earth where men are oppressed in comparison to women.
I'm not even saying any of those subs are good, but nobody in their right mind is going to equate them with people advocating genocide or "incels" advocating rape.
Libertarians can be left-wing, so the premise seems irrelevant to the conclusion.
Had I been familiar with /r/atheism, I might have been able to guess which of those was correct.
But thanks for your “help”.