AI weapons are specially horrific in the way they have potential put massive and specific lethal power under the total control of a small number of people, in a way (like all AI) that basically cuts most of humanity out of the future (or at the very least puts them under a boot where no escape is imaginable).

In some ways, they're even worse than nuclear weapons. A nuclear attack is an event, and if you survive there's some chance of escape. Station 100,000 fully automated drones around a city with orders to kill anything that moves, and the entire population will be dead in a couple months (anyone who tries to escape = dead, everyone else sees that and stays inside out of fear until they starve).

Manpower and attention limitations have been and important (and sometimes only) limit on the worst of humanity, and AI is poised to remove those limitations.