Easy when your adversary has no air defence and no airforce. You sit at 40000 ft and bombs away. Really brave
Unfortunately this is the way of warfare. War has never been a gentlemens game. You take whatever advantage you get in tactics, strategy and technology. Why would the Muricans sacrifice soldiers just to attack a few isis militants holded up in some remote place when they can just bomb it to smitherens with jet fighters and bombers without even losing much.
You had primitive tribes taking on armies with mass numbers of men along with guns and horses along with being well supplied. While tech advanced primitive tribes just had no answer even if they aquired guns.
When your enemies have no answer to your weapons that just makes the job easier.