Why do tolerant people ally with bigots?

What I'm struck by in this piece by Andrew Sullivan is the contrast struck between Bush/Cheney and their party. You can read the piece for yourself and see what I mean, but here is an exchange of some interest:

In Ronald Kessler’s new book on Laura Bush he recounts another incident when Bush invited his Yale classmates to their college reunion at the White House. One of his classmates was formerly Peter Akwai, a man who later had a sex change operation and became Leilani. When Akwai shook hands with the president, she said: “Hello, George, I guess the last time we spoke to each other, I was still living as a man.” Akwai described Bush’s response: “He grasped my hand firmly and said, ‘And now you’re you!’ ”

Nevermind being accepting of gay people, that's part and parcel of being a decent human being by the standards of today. It is actually more difficult to find people who don't regard transgenderism with skepticism or outright hostility, even among allegedly open-minded people - and let's remember, this is George Bush we're talking about.

"And now you're you"? There are a plethora of responses I would have expected to a statement like that, but I would only expect a response of that nature from a genuinely accepting person. (Most people I've encountered don't even believe transgendered people are genuine about what they describe as their inner selves.) I was actually quite taken aback by it. And don't be so quick to discount it, either - that's a lot coming from a Torontonian, let alone a Texan.

And of course there's Dick Cheney and his daughter Mary. What I don't understand is why... actually, not so much why, but how these men could ally themselves with the racists and homophobes and bigots that make up their base.