He had courage at a time when many didn't.
Took a lot of guts to expose something so heinous.
Such pilots hate to land their aircraft in a spot not laid out as an LZ and it is practically against their religion to leave the seat of their aircraft. Young Hugh did both to his great credit.
Stopping the massacre was a good things.
It's exposure certianly was not. This was the sort of thing that should have been handled by transferring Calley to some stateside post and telling him and his men to keep their damned mouths shut, or else, combined with the destruction of as much evidence as possible.
The truth was not worth the price.