Yep. I agree. If you said to a serial killer, "Stop killing it's mean" they aren't going to stop. People are going to act the way they want no matter how it affects other people.
Banning is bit like sweeping under the carpet, it of course helps a little, but they keep coming back, it is too easy to go around the system. It was easier early times, there was no mobile phones then, you used land line to call BBS, there were some who still wanted to make mess, but those were quite easily kept away as we could ban phone number in our system. Maybe some browser and computer finger printing which Google uses as part of their system might help with that, but do we really want such big brother system?