Names aren't changed on a whim, or just because someone wants to it. Oreo's was a special case, whether he realizes it or not.
Osiris wanted the change as WarezMonster was not exactly a great name for a mod, nor did it reflect his actual professionalism.
Saxon had his changed to the name of his company, plus he originally had his own name as his member name.
Mak had his cut down to its current version because everyone just called him Mak and not his full name.