Fixing all the loopholes is hard. Blizzard didn't want to mess up the game when they made the telekinesis skill in diablo 2, but it turned out to be a big problem. Similarly they didn't want you to be able to PK people with no warning, but various methods of doing that emerged. Now for Diablo 3 they're so worried about people screwing with each other that the game gives everyone separate item drops, but something like that is too big a change to just go back and "fix the loopholes" in diablo 2.
I believe that. Not even sure how long that professors griefing was allowed to continue. It sounds as if he primarily had one trick he used, which should have been fixed after a while.
Or if it can't be fixed "physically", then maybe there should be rules and misbehaving players should be evicted.
I hope they won't fix Diablo 3 so much that it becomes boring.
