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.
same w/ climbers. but, climbers need a little attitude. it helps them to survive. that said, most climbers are the best sort of person you will ever know -once you get to know them a little bit. ;)
there is something about the rugged individualist! (wait! ozero used that term in his sotu. aaargh!)