Baloney, that sniper was using a scope. He was watching him from 25 yards away at most, clearly seeing an AR-15 in his hands. Anyone creeping up towards a Presidential candidate with a rifle in their hands, on a rooftop should be shot in sight.
1. The guy was on the opposite side of a sloped roof, and was far more visible from the rear and sides than he was from the front.
2. It appears that the line of sight from the sniper location to the perp's location was at least partially obscured by a tree.
None of this is really germane to the discussion. The question isn't whether the security team should have fired at him or not. The issue is why the hell President Trump was even standing there at all after spectators had seen the perp and pointed him out to the police.