That may be all that it boils down to... however that these folks seem to target cyclists is a key issue for cyclists.

Ran into an interesting dichotomy yesterday on the way home. Motorist in front of me and to my left was just being a JAM... not to me, but to other motorists... he squeezed between cars to jump from the left lane to the right, then back again to the left lane, then when the left lane appeared to slow he again jumped right... no turn signal use, and surprisingly to him, no real progress either... he continued weaving or trying to thread through traffic until he eventually came to a situation where all lanes were blocked and he had no place to go. That was where I caught up to him again. I really wanted to make some negative comment about his driving, and his window was rolled down... so I looked his way just to see what kind of JAM he was... and he glanced over at me and smiled and declared "that looks like the only way to get through." I only replied "Yup" as I slowly made my way past all the stuck traffic.

The guy seemed congenial enough at that moment... yet his behavior in traffic was abhorrent. Hard to explain what exactly his motivation was... he drove like like he had to get to a fire, yet never really went anywhere and ultimately he didn't come off as a blathering idiot. (verses the folks you see talking to themselves and pounding on the wheel) Makes one wonder what went on in his head just moments before... it was obvious that he was driving right into backed up traffic, yet he forced his way around like there was some ultimate reason.