Saw the trick play field goal by LSU and was wondering if it should be legal? Obviously it is at the moment a legal play but I don't understand why it is.

The holder receives the snap, and with his knee DOWN throws a pass...It makes no sense that a player with his knee down would be legally allowed to throw a pass. If he is placing the ball for a kick then obviously his knee will be down, but that should then be the ONLY option for the play unless that player lifts their knee off the ground before attempting to run or pass. Thoughts?