This makes lot of sense to me. Swearing in real-life can be ok in some situations. You can express your feelings very fast. I do it sometimes (e.g. as it took me several days to assemble our kitchen). But when I write a post, then there is enough time to read it again, to think about it and to handle impulsive feelings.

I understand if this happens in a chat though. A chat is quite real-time.
But posts in a forum are visible for a long time (and there is an edit function).

If someone wants to prove that he is a hard guy then swearing is the wrong way, better go to sport or book an adventure travel then.