Earlier quoted context omitted.
Sadly, that's all some people seem capable of reacting to. Those who say that violence never solves problems have never had to live around a sociopath.
But unless you actually kill them, by beating them up, don't you just run the risk of the other person escalating the violence and ambushing you later? You've already established that he's a psychopath and doesn't live by the rules of most normal people, so if you push him down, maybe tomorrow he'll stab you with a knife, run you down with his car, or just shoot you.
Psychopaths are like parasites that feed on what they perceive as weakness. If they lose a fight they're much more likely to move onto someone new, in the same way that the subject of the article continually hopped roommates. Jamison's final escalation was with his brother, presumably after he'd made it clear no more bailouts were coming his way. The end of Jamison's rope was when the parasite realized his past string of roommates were fighting back, and his ability to leech off of other family members was done. Kinda comparable to how a cheetah won't attack larger animals than itself like lions will, because if it gets hurt it can't run fast and eat.