Stigma isn't even the word. You wouldn't say there's a stigma associated with using ethnic slurs, or homophobic slurs, so why should misogyny get a pass?
True, the only problematic thing about this is the exact slur they used. You can perfectly state that they are a-holes, dimwits etc. but some slurs are so minority focused I get why you shouldn't use them. And yet, a perma ban for that? Bit hard, bro.