Because it was clear from the arrogant tone of the author that he was merely attempting to engage in more Southern bashing and employing the usual elitist, bigoted stereotypes. Simply put, he doesn’t know what the hell he is talking about.
What I knee-jerked about was his characterization of Bush as preppie, etc. That's the first I've seen of that and I agree.
I was dove hunting in central Texas a few weeks ago with people I had grown up with, roomed in college with, etc. They are all very conservative Republicans, and all but two are either doctors, dentists, or large corporation VPs. One is a working man, and one is an oil man who bought a lot of oil leases when oil was $8 /bbl. He has 10 times the money the rest of us have put together, now.
Anyway, I hadn't seen them in years and was amazed to hear the vituperation about Bush being a "Texan." The summation was that he went to "Yankee" prep school in the 5th grade, and only returned to Texas to go bankrupt and win the governorship on his dad's name and the disgust with Ma Richards.
Whatever your assessment of their judgment, that thinking is a real phenomenon, and there is a huge divide.