This is a situation, where the top has accepted responsibility rather than pass the buck down (to where the original AAR weren't as accurate as they could/should have been).
Bottom line is one half of soldiers from this Ranger unit was engaged by enemy fire - Ranger Tillman, a fellow Ranger (and an ANA member) doubled back to see if they could be of support - They came upon the ridge after the initial engagement was over - At that time the Afghani and Ranger Tillman were KIA via blue on blue fire....
It awful, but it happens.
God bless Ranger Tillman, he was a hell of a man. But this situation is disgustingly being blown into something it is not. There is no cover-up, there is no conspiracy.
I doubt they are threatening to take away a star based on his covering for underlings.