I frequently have overheard guys (typically the same type) at the gym talking about cheating on their girlfriends.

And granted, joking about rape is very rare but it definitely happens - I was at a barbers getting my hair cut when another client was obnoxiously talking about a girl he knew who was “accusing a guy of rape” and joked about how she probably deserved it if it was true.

I obviously don’t know these people, I certainly wouldn’t tolerate this behaviour in my own social circle.

I think that you probably just choose to ignore this kind of language when it’s strangers and ‘not your business’