Agreed I was being cute there. It was an attempt to stretch my opposition's argument to the breaking point. I would expect the answer to that question to be "Of course not". Then my response is "what makes it any different if the on-rushing lineman hits the guy from behind". Which is what happened here. I wanted people who were arguing that it only matters where the ball lands to think through all of the situations where that could occur and what would differentiate them.
As far as losing control of the ball with your arm coming forward and having the ball go "backwards", if you define backwards as behind the yard line where the QB is standing, then most definitely yes (in fact that's what happened here). Look at the play. I don't think anyone would say that the pass ended up behind the quarterback (defined as behind his back). It went forward in relation to his body plane. When you throw a football, the direction your arm travels is not a straight line directly parallel to your target line. To begin with, you turn your shoulders so that they are pretty much parallel with the target line, then you cock your arm behind your head, which puts it at even more of an angle to the target line. When you factor in that his receiver was running a sideline out pattern, the target line of the throw was also going to be at a significant angle to the yard lines. Add them all up, i.e, the angle of the target line, the amount of turn in the QB's shoulder, and the cocking of the football behind the QB's head and it wouldn't surprise me if the nose of the football was actually pointed directly at the back end zone (in fact, if you look at this gif, you can see that. This camera taking this vid was likely in the back corner of the north end zone and the point of the football is to the viewer's left).
The "forward" motion of the hand is actually a combination of rotation of the QB's torso, the forward motion of the shoulder, and the uncocking of the elbow. The ball doesn't travel in an immediate line straight down the target line, it travels around the QB's body. The point of the football is going to rotate from pointing from the back end zone all the way around to the target line before it is released. That all happens in a fraction of a second. If the QB's arm gets hit enough to dislodge the ball at any point, it is likely to flutter in the general direction of the point of the ball which easily could be behind the line on which the QB is standing.