Think about this scenario, Westerfield sees Brenda at the bar with her swinger friends. He is aware of the sexual antics and wants to be included. She turns him down and openly ridicules him. He follows her home, watches outside while they order pizza and continue their party in the garage. While they are all partying, he enters the house and goes upstairs to the kids'bedrooms, thinking to himself, they can shut me out, but I can still play, and takes the girl.
The parents aren't guilty of anything, except being White Trash.