watch your mouth! o.k. i know what you mean. ;)
I get that from interacting with them in the Sierra Nevadas and specifically Mt. Whitney when I was a lot younger; It seems like they were always from the L.A. area and wore super bright neon clothing.
Their overriding attitude was "get out of my way. I am awesome." They were rude and arrogant in the parking lot, and rude and arrogant at the top, too. They thought only of themselves in an environment where teamwork and mutual assistance was of utmost importance.
Of course, I am making a generalization and most of those I've met on a trail were very nice folks and tended to be friendlier than the general populace, IMO.