I’m generally not a fan of strict censorship or heavy-handed moderation, but if the code of conduct already clearly covers the issue in points 4 and 5, and those rules were clearly broken, then firm moderation might be the only fair option.
Back many years ago, I moderated a large forum that used a warning system. Something similar could work well here: for example, three warnings could lead to a temporary suspension (say, for X days). If the behavior continues after the suspension ends, then a permanent ban would follow.