As a result of Indiana's passage of a religious freedom bill, there have been cries from many quarters that it promotes discrimination against gays and lesbians. All it does is restrict the government from unnecessarily infringing upon the religious rights of it's citizens, it may not even permit discrimination against anyone.
But people have the right to refuse to serve anyone, for any reason, including reasons that the majority does not approve of.
The basic freedom of action that forms the basis of every right enshrined in the Constitution also forms the basis of the freedom to associate. Freedom of association has been recognized in the Supreme Court, but the Court has carved out an exception:
When people work, they are prohibited from exercising their freedom of association. That is, in the primary area of human endeavor, a basic human right must be left out.
But leaving out the right only breeds animosity and resentment among the people who have their rights stripped. And what's worse, because there are only a few limited special classes that receive protection, it spawns a backlash.
This is where the words like "Gaystapo" and "Homofacism" come in: people who would've otherwise not been involved in the debate join the other side, because their friends, associates or even distant political allies are being prosecuted for thoughtcrime - not the refusal of service, but the refusal of service for the wrong reasons.
And for the "wrong" reasons it is - no one disputes the right of a business operator to refuse service to a customer for other reasons, but only it is because they dislike a "protected" class. When the government begins prosecuting people for thoughtcrime, it radicalizes and entrenches both sides of the debate. Side A believes that the other has no respect their right and will seek to eliminate them, and Side B believes that they have the right to demand support from people regardless of whether they wish to provide it.
What's worse is that the idea that one person must serve another and someone else has the ability to demand that service by right, that is a limited form of slavery, or if you don't like that word, involuntary servitude. When seen in it's true light, where the legally superior person can demand, on pain of penalty, service from a legally inferior person, it is revealed as morally abhorrent.
And simply acknowledging the right hardly constitutes a return to segregation. Jim Crow was only able to exist for as long as it did because it was enforced by law. It was legally required segregation, not legally permitted. Because the law does make it universal, discrimination would carry a high price.
Profits from minority groups would be sufficient to convince most private companies to get in line, and public avoidance of discriminatory businesses would convince all but the most recalcitrant actors to concede to public pressure. The solution to unwelcome but not violent behavior is social pressure and isolation, not incarceration. It is, of course, far easier to pull a gun than organize a boycott, especially when the public generally may not back such an action.
Not only that, but discriminatory conduct carries it's own costs. If one seller refuses to sell to a specific group, he gives that part of the market over to his competitors. If an employer refuses to hire certain groups, he ends up paying more for inferior staff, because he limits his labor pool. If discrimination isn't protected (Davis-Bacon) or enforced (Jim Crow) by law, it eventually destroys itself.
And letting it tear itself apart doesn't create new allies for it.