I think fear is fairly subjective, and to me these are scarier than bombs and guns. Bombs have a blast radius and bullets don't stop after they hit their target, which means collateral damage has to be considered before using these. If you don't have to worry about that because you're going to just drop an anvil on someone's head it would make it that much easier to order someone's death.
Like yeah you're probably not going to see any mass killings with these drones, but it certainly makes individual targeted killings easier.