Secondly, there have been bans for people repeatedly ganking (griefing so you wish) people. You can deny want you want, but for once use Google and you'll be amazed by what you find.
Thirdly, again use Google and you will find cases of people hurting themselves because of a game. You can deny that what you want, but sadly it's true.
So back to my question: why do you have fun hurting people?