Revealing mistake: When the two station reporters are investigating Eddie's room, as the female bends down to the table, she is scared by a dog. In one shot you can see a black wire on the dog. (00:14:55)
Revealing mistake: The final shot of the sex-scene between Bill and Marsha is very obviously a piece of (rather cheap-looking) 2D cell animation. The actors look like cartoons, the fire is simply the same few frames repeated over and over and the background looks obviously painted.
Answer: He hated the way they were living. Acting human, hiding who they truly were, integrating into "normal" society. He wanted to be wild and free. When they were feared and worshiped.