I could be wrong, but I don't think anyone on this board is advocating excluding gay people from places of public accommodation. But there is a big difference in requiring Target, Lowes, McDonald's, etc., to serve gay people and requiring a bakery to bake a wedding cake for a gay couple. The former ensures that gay people can have basic services and be integrated in daily American life. For some, the latter goes to the heart of a moral/religious objection surrounding gay marriage. I'm not sure exactly where to draw the line, but I think those providing services for weddings, at least, should be afforded an exemption from accommodation laws requiring service to gay people.
Using the same logic, a mom and pop pizzeria could discriminate against black people, because their faith includes white supremacy and the separation of the races, but McDonald's couldn't. There's no difference whatsoever other that those who want to rationalize their discrimination object to being lumped in with white supremacist.
Who gets to decide which faiths and which bigotry is "justified" and "legal"?