A man who is going to shoot the president does not buy a gun via mail order that can be easily traced to him.
A man who is going to shoot the president does not carry a large "gun shaped" parcel to work with him in the morning that anyone can see.
A man who has just shot the president does not hang around in his workplace so he is standing there when the police arrive.
A man who has just shot the president does not leave the gun (with his finger print on it) and bullets lying on the floor. It was obviously planted there.,
A man who has just shot the president does not look so calm and collected after being arrested and say he was a "patsy".
Don't you think it was an amazing coincidence he just HAPPENED to be working in a building that overlooked the route the president was going to take, in a building on a bend so the car slowed down making it easier to shoot someone.
Don't you think it is strange that it just HAPPENED to be lunchtime when the presidents car drove past, so the floor Oswald was working on was empty, everyone was a at lunch.
I do think there was some VERY strange goings on with Lee Harvey Oswald (his trips to Russia, his ability to get back in to the USA from Russia so easily, his strange pro / anti castro behaviour and much more).
But I don't think he was that bright, and I think he WAS a pasty, and only when he realised he had been set up for the JFK shooting did he rush out the building in a panic.
A sharpshooter sat at the window with a gun a shot JFK, then left the building with his gun. Another person planted the "Oswald gun" by the window.
Other people shot JFK, and Oswald was a bit player in the whole thing.