I had this debate with other mods on r/cscareerquestions a few years back. My preference was for SomethingAwful-style modding transparency, where your bad post (usually) stays up with a note that says "USER WAS BANNED FOR THIS POST", and in fact there's a global listing of all the recent bans, including the user and posts in question.

The other mods largely preferred invisible modding, that "stays out of the way", that doesn't draw attention away from productive discussion.

I'm not sure either is obviously a better methodology, honestly.