Much of the basis for arguing against allowing small business owners a ‘right of conscience’ religious exemption from providing services to same-sex weddings is an assumed equivalence between sexual orientation and race.
Given the long legacy of slavery and Jim Crow, federally enforced nondiscrimination laws were necessary to allow African Americans access to commercial services available to whites, not to mention voting rights, employment, public accommodations, etc. Advocates of forcing religiously conservative bakers to produce congratulatory wedding cakes with two grooms or two brides atop suggest that the same thing is true of gay people. It isn’t.
Most bakers, florists, etc. would provide these services; allowing a small number to opt out based on religious conscience shows respect for individual liberty that in the long run will serve gay people much better than using the law to force expressive behavior that celebrates same-sex weddings.
Some defending such a draconian application of anti-discrimination law put forth a Manichaean view of good progressives vs. evil traditionalists. That self-congratulatory perspective is blind to the shadow side of leftism/progressivism and its tendency toward collectivist authoritarianism when given a free rein. There’s a striking similarity between leftwing and rightwing inquisitors and heresy hunters.
As Matt Barnum writes at The Purple Elephant blog:
I think we should be uncomfortable making a direct comparison between discrimination against gays and discrimination against blacks. Both have been awful, but only one involved slavery, only one involved de facto and de jure segregation. …
The root of this awful argument [against religious exemptions for service providers who oppose gay marriage] is the notion that race and sexuality are exactly the same—have the same moral status, the same cultural history, and warrant the same legal response. There are certainly overlaps, and gays have certainly been treated very poorly historically. But sexuality is not race, and it shouldn’t be treated as such.