"These [Southern whites] are not bad people. All they are concerned about is to see that their sweet little girls are not required to sit in school alongside some big overgrown Negroes."
The above quote is what President Eisenhower said to Chief Justice Earl Warren at a White House dinner in 1954 (copied here from Digital History).
In theory, Eisenhower wasn't against equal rights. He just empathized with Whites who didn't want to get too close to Blacks because they felt that Black people where inherently dirty.
Those who support a business owner's rights to selectively refuse certain services to gay people while agreeing with his or her obligation to serve gays as long as they don't have to get up close and personal are reflecting Eisenhower's bigotry.
It's not about religion. There is no biblical distinction between serving pizza to gay people and catering their wedding. If your not killing them, you're not following Leviticus. That's a good thing, by the way.
It's about cooties. There are thousands of ways to disobey God's law (here's 10) and many of us do so on a regular basis without being discriminated against by local merchants. But like the good ole Southerners concerned about their daughters sitting next to Black people, some people find the idea of being too close to gayness revolting. That's not faith. That's bigotry.