Having worked with the USAF on many occasions over the years I am sadly not surprised when incidents like this happen. Part of the reason may be that American forces just have too much live ordnance in their training. As a result I think that they lose a little of the respect that is essential in handling live, extremely destructive weaponry. I certainly know that UK forces have such limited access to live weapons that when you get one, all contingencies are briefed to death and before you press that button you make damned sure you know that the site is on the target. In my experience in working with the US military it is often the case that it's "just another standard mission, only 4X Mk82, good job, outstanding".