That "bumpkin" was a former Marine.
Two of your "most difficult shots in history" were with a scoped rifle at about 60-80 yards. The other one was a miss. If that is some sort of unprecedented feat, you need to run around during deer season and tell all those carcasses tied to people's bumpers that they can't possibly be dead.
The problem ain't what you know. It's what you know that ain't so.
Most Marines can shoot.
Not all.
To compare this with deer hunting is ridiculous.
The shots (according to you) were at a downward trajectory with the target moving away from you and a tree conveniently in the way. In less than 7 seconds.
Oswald didn’t do it. Yeah, he probably was involved in some way. But the team was either two or three individuals shooting from triangulated points that yielded a flat trajectory.
Cripes, you can find the pictures that show the people in the area pointing towards the grassy knoll.
BTW, I used to shoot quite a bit, and while I pretty much gave up hunting years ago, my brother who is a very accomplished white tail hunter in upstate NY has repeatedly told me to my face that I’m a far better shot than he is.