All over the internet, Conservatives have been standing up for bigots who don't want to do business with gay people. "They can just go somewhere else!" they exclaim. And on its face this is actually a true statement. They very well could go "somewhere else." But where is "somewhere else?" That is the question which is never answered.
This argument actually has its roots in the "separate but equal" dogma that delayed civil rights and sought to provide a parallel society for blacks, so that white people didn't have to face integration. "Not one drop" rules were applied throughout the Confederate South - if you had any relatives going back several generations that were black then you were no longer allowed in the tier 1 white society. You were relegated with the undesirables in the tier two society. In the ideal universe of the social conservative would not one drop of gay be allowed? Any man who ever kissed a man is ineligible?
"Not one drop" caused "passing," where people of mixed background passed as "white" because the racists couldn't sniff it out. The same would be true for gay people. Only gay people who couldn't "pass" as straight would be affected by these laws. Although none of these conservatives would ever go so far as to say that they are asking for a 'separate but equal not one drop' society for gays, that IS what they are asking for.
When you say to someone that they can 'go do their business somewhere else' a few things are forgotten. In order for that person to be denied business, they had to expend time and resources to get to that business. And then they will have to expend more time and resources to get to the next business (which could also end up being a gay hating business). That is something that only gay people would have to deal with, because there simply are not any businesses in America which refuse to do business with straight people.
When the argument is extended to racial relations it becomes clear what it is:
Social Conservatives desire a parallel society for homosexuals where they are "separate but equal." That's why they insisted we should call their marriages civil unions. That's why they deny that the state can and does oversee marriages. And that's why they argue that you should just get your cake somewhere else, because, we need "separate but equal" cakes.
The bottom line is that gay people pay taxes and join our military. They are therefore members of the public, and the law was long ago settled that when you open a business you are serving the entire public, NOT part of it. We have forced racists to serve blacks for years on the grounds that they are taxpaying members of the public. There will be no separate but equal this time. We will call this argument what it is and we will blow right past it.