In Oct 2015 (rough figures as guide, impossible for me to study properly) created accounts consist mainly of (or i was just very lucky to "hit" target)
Accounts between 572000 and 575000 are "btcRDkill_"
Accounts between575000 and 600200 are "MrFudged1_"
Accounts between 600200 and 625000 are "KNC_areThief"
(all followed by different numbers)
Over 50 thousand there. Again, i know these aren't "all" countable, but most seem to be. Have a go yourself. (i have no tools here) Pick a number between u=572000 and u=625000. Which one above did you hit?
Also endless (unused) MMMglobal accounts. Are they responsible for all of this? Pick a number between OP target u=600000 to u=700000. (guess, 1 in 5 chance to hit)
Also the strange letters at the end of names I previously mentioned, and Connected. Take your pick of target u=, very good chance to hit.
These accounts are All(?) inactive?
Are these accounts already banned? Or just waiting. I cannot know.
I can assure you that those accounts have been banned. Just because someone is listed as a member, doesn't mean they aren't banned. Only the staff can see if a user is banned or not.
Anyway, moderators cannot ban members (because of how SMF ACL's system is build), only global moderators can, so we, as normal staff, really can't do anything. There is just one exception: Newbies. Those members can be nuked (but not banned) by Patrollers, which we have done with those MMMGlobal and KNC accounts (and of course the bot helped a great deal).
You have no rules. Only vague rumour, open to individual moderators to enforce.
Maybe you should read:
Unofficial list of (official) Bitcointalk.org rules, guidelines, FAQ
EDIT: Updated my post to be more clear.