Yes Phazael, mistakes happen. Just because you have drones in the sky, doesn't mean you somehow have perfect missiles or perfect people operating them.
Did the rebels in Ukraine intentionally shoot down M17 knowing it was a civilian plane?
Did the US intentionally shoot down IR655, knowing it was filled with civilians?
Did the US intentionally bomb the chinese embassy in Belgrade?
I mean, I feel like it shouldn't be necessary to explain that mistakes happen, but it seems you are confused on the subject.