What makes him tick, in my opinion, is power and control. I hesitate to type this because I don't want it to be misconstrued as empathy for RH, but I think there is a great deal of self loathing at play here. I think he felt shame for these urges. How do you reduce the shame ? You shift the responsibility. " If YOU weren't this, I wouldn't be this "...that realm of thinking. I think we see that in his calls to Melissa's little sister. Did he want to torment her ? Absolutely. But within that he also displays venom at the profession itself...as if it's very existence somehow MADE him do the things he did. It didn't , of course, but I think he tells himself that it did.
JMO