If you believe that AI is powerful enough to help the good people (however you define that), why isn't that also coupled with the belief that it is powerful enough to help the bad people (ditto)? Either the capability of this tech is completely overblown or it can help a wide swath of people including those with conflicting ideologies.
I absolutely believe that AI can be used by bad people in harmful ways. I don't think that's going to take the form of mass murder. I don't think knowledge is the missing component there.