Again: The platform is IRC. The servers are the individual communities. There were hundreds of IRC networks. You were not blacklisted from all of IRC. You were blacklisted from a particular server. And in my personal recollection, you only got banned for something especially egregious, not like today where saying the wrong "trigger word" can get you shadowbanned, which is even more nefarious.

On top of all of this, bans were frequently appealed and overturned.