I noticed that there are other duplicate group names (as there are many "Bruno" on earth). A name is not sufficient to make an unique identity. Computers often need an unique ID, like it seems to be the case for IRC and group chat (I actually tried the group chat in second AD group and I got a "you have been kicked" too).
Concerning the Community rules, I experimented some disagreement in the past between myself and "the Community" represented by some famous veterans at the time (including Auntdean). I could feel offended several times by attitudes or acts or says about me and it was not fun.
I could even be (implicitly) "banned" from a moderated group (e.g. not accepting my candidature to join). No fun, but this is the liberty and need of any subgroup, and for overall "buffer" and diversity of research.
I agree that temporal banning is a violence but that it can be necessary for the fun of majority in local situations (like in global chat, veteran chat etc, one by one, locally). Exactly like in real life, if somebody starts to cry, or repeat himself etc in a small group of people: or the other ones go out (it's easy to escape a turbulent discussion on chat: just don't read, don't react and the time zone will do the moderation), or, and that is the question here, some appointed "police" do the job of banning a disturber.
The point in "banning" is that it does exist in real life only in one situation I believe: in case of some danger (the need to protect integrity of persons or common good). In this real life case, there is an impartial judgment from some external judge, after some possibility to "defense" himself etc.
In Foldit, I remember one case of player's banning: it was linked to a player posting a recipe that would be able to cheat (copying another payer's solution). This case really endangered the all Foldit game concept; it was not "semi-external" as chats aside playing the game.
This to say that I'm not sure banning is the right tool to moderate a global chat: it is too "dictatorial" in my opinion. When I see episodes of "classroom" chats in the global, I simply stop reading and it's ok, it stops by itself (sometimes after careful intervention of moderators), the best way I noticed to "counter" this beeing to turn speaking about puzzles and tips.
After all, I find this subject quite interesting. It's common to many media on the internet. No one got THE solution yet. An interesting research area per se.
Take care and happy folding (and/or social experimenting) all !