Ug Betrayal possible explanation....
Maybe it wasn't the real Ug. I mean, how do you tell one shapeshifting faceless bounty hunter from another? He coulda just said he was Ug to play off of Charlie's trust. He certainly was more eloquent than the Ug we remember.
He asked us, "Be you angels?"
and we said, "NAY, we are but men," ROCK!