I get the rule and the intent, but today, Dalton drops back to pass, and his hand is literally facing towards his own end zone when it slips from his hand and goes back.

Same thing when they're trying to determine if a quarterback's arm is going forward to see if it's an incomplete pass or a fumble. If the ball went lateral or backwards, why does it matter what the arm was doing? By definition isn't a pass that doesn't go forward a live ball? So why is it not that way if the pass wasn't intentional?