JD is hated by the establishment because he was fighting against illegal immigration when the establishment (including Bush) was pushing amnesty.
And JD was persona non grata at the Bush White House. He was not liked by Bush and Rove because he consistently opposed their amnesty schemes and supported border enforcement all through W's two terms.
JD was disliked by Beltway insiders, elitists and crony Republicans. I have zero respect for a list of crony Republicans who were closer to JD on the issues, but supported their Washington crony McCain for reelection. That's the sort of thing that continually undermines the Republican party.