It looked like the rider was consistently making the noob mistake of riding just left of the fog line. He is "inviting", the unsafe passes. One needs to either commit to the shoulder or take the lane. You can't try to take just a foot or two of the lane unless you want trouble. As for the OP:
1. Most of the roadways didn't look like 50 mph roads to me, but I could easily be wrong here.
2. Marathons aren't bulletproof and there is some virtue in speed and the ability to accelerate. Marathons interfere with both.
3. Sure, carcissists are a bit more likely to aggressively express their bike hate if you are either in spandex or look like a homeless person. But there isn't much joy in the happy medium between those two either. Sometimes the clothing is just functional.
4. If one only leaves the shoulder when there are no cars, one is not taking the lane at all.
5. The cars are attempting to squeeze by because the cyclist isn't taking the lane.