Testosterone isn't a good explanation for why humans accidentally make other species extinct.

Pinker has decent arguments for declining violence and for expecting people to overestimate some risks. That isn't enough to imply we shouldn't worry.

Pinker's model of war says the expected number of deaths is unbounded, due to small chances of really bad wars. His animal rights thoughts suggest AIs will respect other species more than humans do, but "more than human" isn't enough to imply no extinctions.