The above quote is straight out of the NFHS Case Book. AlUpstateNY, the defensive player was going into the gap as witnessed by his right leg's position with the center's right leg. If you will admit that the defensive player was shooting the gap, what else could the umpire have possibly seen to justify that flag?
I understand the rule, know what it says and don't doubt that the rusher's intention may have been to "shoot the gap", but I can't tell whether or not there was direct contact on the snapper by the rusher, before he got to "the gap" or
before "any simultaneous contact with another A player" was initiated, and neither can you.
I am suggesting the Umpire was in a position to observe that action, and may have seen something from his angle that is NOT viewable from the camera's angle. Of course it's pure speculation, but he may have seen contact with the upper right side of the rusher, contact with the right forearm of the rusher or any other contact that the snapper's body shields from the camera.
Usually, when the covering official is in the proper position to make a call, is focused on the area in which a call was made, I tend to give him the benefit of the doubt that he may have seen something that a camera angle doesn't show.