some aren't.
Some motorists can be jerks, some aren't.
I ride single file on roads (back when I used to ride on the road), and would pull over if there was a line behind me, or someone refused to pass.
In most cases, a few seconds or even minutes isn't going to ruin someone's commute unless they are just an angry person.

But, as I said before, I just don't ride on roads anymore. The idea that someone would endanger someone elses life because they are inconvenienced is sad, but our current reality.