I agree that certain moral standards should be applied, like you say Sharazhad, but there are few "variables"...
Mur is doing it for his personal benefit? What kind of benefit? Cognition? Isn't it the same benefit as the student that researches human behavior you mentioned?
Bottom line is, this is Mur's game, and he made it clear on various occasions and on the very site that this is an unconventional "game". He is not making the game to make YOU relaxed, and wherever you go, you will be someone's "pawn" in one way or another. When clicking a youtube video, you are someone's "pawn" in achieving higher views number, for example... It's a relative subject.
The problem is when you damage people in a way, then you need to explore the whole situation. Ok, you list psychological experience issues in MD - what, this game has potential to make conflicts between people?! That is what every community has in itself.
This is a game that is supposed to bring experience to people (and experience of those people to the game, meaning Mur). Conflicts are IMPORTANT part of experience.
If Mur encouraged certain conflict-making, then it is his decision to do so - it is your decision to accept it or not, to conclude is this the last line that couldn't be crossed or not quite yet?
There is a certain inconvenience when you take Mur's decision to high standard and get offended when he thinks differently than you. He is not perfect nor best of us all, and this was supposed to be a community of intellectual independent people, that know how to avoid identity "mass-production" that is so frequent in reality, yet there are many people here, experienced too, that take Mur's words for granted and use it as some kind of axiom, and eventually get shocked that one of those is contradicting to their own logic - then mental chaos emerges! x)