You really can't think of anything? How about giving a fleet of AI drones a large supply of bullets and telling them to go kill everybody in some region or of some group.

Widespread mass realtime facial recognition usage is allowing governments to target and repress subsets of the population with an unprecedented scale and efficiency. ICE are flying facial recognition drones over sidewalks in downtown LA. Dissdents are having their facial geometries entered into secret databases simply based on political opinions.

Any new technology throughout history has first been used for war and genocide.

How could modern AI have helped those groups you mention in their endeavour? Really fucking easy and effectively, and you don't need a lot of imagination to think of how. From surveillance and interrogation to pinpoint determination of ethnicity and much more. Not to mention translation between human languages.

> the nazis more effective or the khmer rouge.

They literally targeted people for their past opinions, how they looked, etc. which you can now determine and process at break neck speed, you can even remove humans from the loop and have the machine determine who's an undesirable or not.

How is this a serious question lol?