The US has accidentally killed plenty of civilians, of course. In the past (in World War II, for instance) they've also killed civilians deliberately. I'm not arguing that the US's hands are clean. But the US also recognizes (now, at least) that it is extremely counter-productive to kill civilians. That's why they order soldiers not to and why it is officially against the law of the United States as well as international law, and a war crime, to target civilians. It is not part of the official US strategy to target civilians - in fact it is part of the official US strategy to not target civilians. On the other hand, it is part of the official, stated strategy of ISIS, Al Qaeda, Al Shabaab, Boko Haram, and other terrorist organizations, to intentionally murder civilians in the most visible way possible.
*Edited to acknowledge current reality vs our past