The government has a vested interest in preventing discrimination at private enterprises because potential revenue is generated every time an economic exchange occurs. Jim crow laws in the south were a complete failure and led to separate facilities that were underfunded and unequal. If you want to operate a business in the jurisdiction of the United States, you shouldn't be allowed to discriminate against customers because you are losing revenue for your business and the state. With that said, I don't think businesses should have to fill stupid requests like a inappropriately shaped cake (see Miley Cyrus) for a gay wedding. I know this example is stupid but it illustrates the point I want to make. You should be able to refuse service for unconventional requests such as inappropriate cakes. But if a gay couple wants you to make a traditional wedding cake, you should not be able to discriminate against them. Basically, you don't have to accommodate customers who ask for unconventional things but you can't deny them service just because they are a minority.