I hope you do realize that's a very very poor excuse to justify his behavior. I understand that he may not be an ass, but there are many other important personality traits.
I'm not justifying his behavior (I actually condemn it), I'm just saying that this is probably the reason behind it, instead of him wanting to just use girls. The problem with moving rooms is just too much- Even if there is a room available, I don't want to have to move all of my stuff. It's not worth it. I feel like I may have painted my roommate as awful (I was pretty irritated when I posted), but we really do get along; he is tidy, doesn't leave shit around, isn't an ass to me (excluding the circumstance). This problem we have right now is really no big deal, but it's big enough that I'd like him to stop. I don't want to risk having to go through the hassle of moving and then getting an even worse roommate. That is my last resort.