Because MU is the game with the most noobs.
There are always some nabs who like to ddos the server,etc.
Take the habbo server for example.
It didn't last for 1 fucking day, cause noobs kept ddos'in it.
Well, if the owner of the server thinks he is better than everybody else just cause he gets to use RZ's name then it will obviously happen.
Well, it's one of the biggest reason servers shutdown, due to the admin either being ghey cause he banns everyone, or lack of knowledge, which leads to server shutdown.