Cyber did nothing wrong by administrating punishment to people who well deserved it, but permanently banning them is something completely different. If this was a reoccurring problem as stated, a temp ban would have work, which should have increased over time.

If they happen to rejoin in a week, then that obviously means this server meant something to them, and they'll have learned their lesson and start to abide by the rules, or not. If they do, that just means there's a few less people who will break the rules. We'll never know if they're capable of changing if these bans were to remain permanent.