No, I think Ron had it right. The country is pretty split on the gay marrage issue right now, but if you asked a good sample of Americans if they thought a lunch counter owner should be willing to refuse to serve black folks, a vast majority of Americans would be OK with a law preventing that. That that same law can then be expanded to include other groups wouldn't cross their mind.
The majority of our nation disagrees with most of us here on the concept of freedom of association.
Actually, I think they should be allowed to refuse service to anyone regardless of reason. If they choose to discriminate based on race, orientation, hair style, or number of vowels in the last name, then so be it.
And let the market respond as it sees fit.