Ok, call me confused. You first ask for specifics, then readily concede that it likely happened in some cases. If it happened in one case, that's too many. As I told someone else in this thread, it only takes one murder to make you a murderer. Everyone after the first is just a matter of scale.
Your idealism is amusing, but ultimately naive and self defeating. By the same token you should join the far left in condemning the U.S. in every single war it has ever fought, because there's always been at least "one case" where some of our soldiers did something to civilians that we're not proud of. By your reasoning that makes the U.S. army "murderers," and renders all the good accomplished they've accomplished in every previous war moot.