On balance I'd say probably not really a red, but it was nasty and dumb, and dumb tw@t moves like that are always a risk plus Moriarty's knee to the back was a stone cold red anyway, so no sympathy. You can't really complain that a clothes line to the chin of a man without the ball gets you sent off.
Gloucester played well for much of the game but lack of clinicalness and those 2 stupid fouls easily could've lost them a game they dominated. Edinburgh should feel seriously disappointed they didn't put them away.