Is it an idea to make a comm for like community-crit to handle these things, or even bring it up in a self-crit comm?

I honestly think this is a REALLY bad idea. It would probably just descend into petty arguing and daily struggle sessions within a week.

Here's the best form of self-crit, the mods ban you and if you manage not to screw up the same way again on your next alt, I guess you learned your lesson.

Personally I think this post was I'll advised, should have just banned the user.