Since the drone was undetected, they could've have informed the ground patrol of the convoy heading their direction, kept the choppers in the air, followed the

Since the drone was undetected, they could've have informed the ground patrol of the convoy heading their direction, kept the choppers in the air, followed the convoy, and acted as soon the supposed terrorists engaged. If the convoy really headed the patrol direction, they would even have intel from the ground. The problem is that you have here a military force doing the equivalent of police work. They are on war mode, shoot first ask later, be on the "safe" side, which is incompatible with how you're supposed to work when you have civilians everywhere. If civilian casualties mattered as much to high command as troop casualties (and it should, not only for humanitarian reasons, but also political), the decision making would be different. The US has one of the best military in the world, they have the technology and the means to avoid collateral damage, what they lack is a change in culture if they're going to act as a peace force.