Domination and killing don't have to be mutually inclusive. Take your example with the ants -- I'd argue that by being a human being, you have dominated the ant

Domination and killing don't have to be mutually inclusive. Take your example with the ants -- I'd argue that by being a human being, you have dominated the ants. Humans have taken over the entire world and shaped it to their liking. But that's actually been really good for some kinds of ants that have hitchhiked on our boats and infested new lands thanks to our intelligence. It's not so much that we know for sure all AGI will be expansionist -- it's more like "there's going to be many AGIs created by humans, so the odds are high that at least one of them is expansionist and dominating". All it takes is one expansionist AGI.