The most dodgy thing is how a cop can see a shooter and Trump isn't scrummed in seconds. Probably incompetence, possibly not but they need more than "trust me bro".

Side issue to my mind, but OK, let's consider. You are absolutely right that Trump rally should have been aborted for a spell, considering there was a report that somebody was in a position to take the shot and nobody knew whether this was one of 'ours'. Just one of the incompetences of the senior SS team. There is still a question of planning. Maybe just me.