For the exact same reason the GOP-E is upset when Santorum beats Romney. These are all urban elite liberal snobs (look at Peggy Noonan for an example on the Republican side) who have disdain for flyover country and little connection to it or understanding of it. They think the candidate who appeals most to urban elite liberal snobs will win the election. They probably would have organized Operation Chaos to vote for G.W. Bush over McCain if they thought of it too.
That’s valid.