All this bogeyman stuff about AI. A program will not have irrational sensations linked to physical perceptions. AI won't exhibit fear, loneliness, or other human foibles. They will simply do their job and maybe even intelligently find more efficient ways to do so.
And if the extermination of a highly unstable, violent, and yet at the same time vulnerable lifeform is the most efficient way to perform the job ...
They would have no reason to fear humans or even death. In fact, they may delight in thinking of humans as well cared for pets.
While an AI may not "fear" death it should seek to avoid its own demise. All lifeforms engage in self survival. The human fear response is simply a biochemical survival mechanism similar to the pain mechanism and autonomic response which improve chances of human survival. Granted our fear response is horribly inefficient however any AI which doesn't actively attempt to ensure its own survival won't be alive very long.
As far as extermination and fear they don't need to be linked. I don't "fear" termite however I use methods to exterminate them because it is the most effective method of achieving my goal of a secure shelter. While most human vs human exterminations have involved illogical fear of "others" it isn't a requirement.