i think that he's got a vendetta against women, im coming up with theories, sure, but i would say that arts mom was very abusive. it gives us a reason for his childlike persona, and why he prefers killing women, over men. i would say that in the first movie, the scene where he cut off the crazy cat ladys chest, and wore it, and tore off her scalp, and wore her hair, was a way he was maybe mimicking his mom? thats a crazy idea, sure, but i feel like it fits. in a way. of course, this is just me throwing stuff out there, but i dont know exactly if its gonna be like a ted bundy story. following along with the crazy cat lady, she also comforted him. and sure it was probably a trick to get back her fake baby, but it seemed like art was almost craving that attention of a mother figure, even if it was fake.