I thought it was just ban evasion (and in the case of s/GenderCritical it is) but you're right, even in subs where none of their accounts have been banned they still post under different names. My guess is that they post to the GC sub first, get banned or have their post removed, and then spam other subs with whatever account they are signed into at the time. Rinse and repeat.

I'm saying they instead of he because they've talked about their vagina in the past, but of course that doesn't mean anything coming from someone like this. I do suspect it's a man.