Hmm... I assume conscious volition in others, and I find most drivers more or less cooperative. I don't see a contradiction. I know some drivers are aggressive, some are rude, some aren't focused, and I think some intentionally block others from speeding; but most see cooperation as in their best interest. 

The larger point is what, not why. On every trip to or from Portland in heavy traffic, I notice cars driving in packs with a mile or more between packs of ten or twenty cars. Why do they bunch up? It is always behind some slow driver in the left-hand lane. This represents lost time to a lot of people, and what strikes me as an unnecessary inefficiency. Maybe the "why" doesn't matter, but when I am passing and cars bunch up behind me, I speed up to pass, and then get into the right lane. If others want to go eighty, that's no concern of mine, except that I don't want them crowding my tailgate for miles.

Self driving cars would eliminate the human element and promote efficiency.