Collateral damage used to connote unfortunate, accidental, regrettably unintentional death and destruction committed in the quest of accomplishing a greater good--admittedly a doubtful and shaky definition to begin with. When collateral damage becomes routine, massive, indiscriminate and random, the consequences deserve more thought than simply dismissing the incident as, oh well, another dead innocent civilian or two or three or tens and hundreds.
Use of drones can come back and bite our collective ass. See arguments presented on why drone warfare is illegal.
Drone warfare is unlikely to become a topic of presidential campaign and debate but thoughtful Americans, perhaps a contradiction in terms, need to think deeply about this practice before the joystick jockeys wearing uniforms begin to think of this exercise as just another video game.