It's very nice that he believes this, but he couldn't be more incorrect. The fact that there are _nurture_ reasons that hate gets reinforced does not actually mean that its basis is not in _nature_.
As a comparison, imagine something much less controversial: mothers deeply loving their babies. The mothers are told that they must love their babies, they're shown examples of loving their babies by all of their peers, their own mothers. The hospital just _expects_ that mothers will love their babies! Clearly this is just a social construction, and tabula rasa mothers might have a 50/50 chance of loving their babies.
This is an intentionally absurd example, but I hope it paints a clear picture; there are lots of ways in which the expectation that mothers love their babies is socially reinforced. But the fact that there are social components to this psychological state does not actually tells us anything about whether or not it's innate.
This doesn't mean that everything is nature, but people seem to be exceptionally bad at figuring out how nature and nurture might interact. Now, it's clear that nurture can either inhibit or reinforce our innate traits, and with something like outgroup hate it's clear that we'd need to acknowledge that it is impossible to extinguish, but possible to minimize.
tl;dr: `Hate` is typically caused by family/society: most Monsters are made, not born. It's usually the result of early life trauma developing into ignored addiction[s] (with certain predispositions as exceptions, of course).
Trivia from Panzram: he helped build Leavenworth Federal while he was serving time for murders/rapes in Leavenworth State; then later served an additional sentence (for murders/rapes) in the prison he helped build.
