Apparently, at least one too many.
Too many people are idiots with social media. In this case, I would guess one of his FaceBook "friends" was a lefty who decided to screw him.
Stay off facebook. Or at least, post with the viewpoint that anything you post WILL be seen by a humorless HR person at your job.
So are you saying that what he did was all right, and the only problem was that he was caught, due to a traitorous friend?