But the 20th century suffered "two" ideologies that led to genocides. The other one, Marxism, had no use for race, didn't believe in genes and denied that human nature was a meaningful concept. Clearly, it's not an emphasis on genes or evolution that is dangerous. It's the desire to remake humanity by coercive means (eugenics or social engineering) and the belief that humanity advances through a struggle in which superior groups (race or classes) triumph over inferior ones.

I don't think aggression works like thirst or sleep. I think aggression is more elicited by particular situations. I think it can be mitigated.

We can make fun of hockey fans, but someone who enjoys Homer is indulging the same kind of vicarious bloodlust.

A decent government with an effective, but not gratuitously violent, police force and a fair court system are essential. This deters and incapacitates psychopaths, bullies and hotheads - and if it earns the confidence of the people, they don't have to become violent in self-defence.

Art works because it appeals to certain faculties of the mind. Music depends on details of the auditory system, painting and sculpture on the visual system. Poetry and literature depend on language.

Photography is a kind of virtual reality, and it helps if you can create the illusion of being in an interesting world.

Commerce, trade and exchange make other people more valuable alive than dead, and mean that people try to anticipate what the other guy needs and wants. It engages the mechanisms of reciprocal altruism, as the evolutionary biologists call it, as opposed to raw dominance.