War is about winning...
... so it is inevitable when soldiers on one side whoops it up when they finally hit something. Especially in a war that has lacked any long term engagements, but has been a series of skirmishes and booby traps. It is human nature to be glad to have finally done something. Heavy action for weeks at a time, would normally result in soldiers that would be a lot more somber, or perhaps just weary.
As far as the military claiming they don't know what was going on, in a given day, they still don't. Yes, they might have a zillion incident reports, but those are just reports written hours or sometimes days later. And that is just what the soldiers saw. How many combatants were really there? Those reports will never contain every relevant detail, because it is impossible to have complete situational awareness.
War really doesn't change. It is boring, dangerous for everyone, and even more dangerous when people get bored, because they get sloppy, or overzealous. And ultimately, when you kill people, it is a messy emotional business. But "Faill America"? No, that is just how war is. Your country would be the same if not worse at war.
BTW, the US military is in Afghanistan at the pleasure of the Afghanistan gov't. If the gov't asked them to leave, they would. It can't even be called a "war" anymore. The Afghanistan gov't ultimately will cook up some sort of power share deal with the Taliban, but the keep the US military around to keep pressure on the Taliban and various other warlords to come to a settlement.