I see it all like this when I'm in a dream:

it is in my mind, my world and my reality. if I want something i will have it, no mather the obstacle. And since it is in my reality i can decide if it is against MY morals. If I feel murder and rape is okay in my dream then it is, and another i might think, no it's not, so i chill.

I believe people are restricting their fun in dreams if they worry about morals.