Let's consider the case of a disabled person. As a class disabled people are a small minority that doesn't on average possess great wealth. A business and indeed in some areas all or most of business in a category may profitably choose to focus on other customers and make it impossible for such customers to avail themselves of that category of good or services.

Then consider black diners during segregation. Minorities like disabled folks are a minority of the population with a proportionally even smaller portion of the wealth. Like disabled people they could be unprofitable to serve as bigots may not want to sit down to break bread near minorities.

In both cased we decided as a society not to give merchants a choice for the overall good of society and those folks.

Furthermore ensuring businesses are conspicuously made to do normal things like serving all customers sends a not so subtle signal that those people are normal and acceptable and those attempting to isolate them are transgressive.

If we can leave off speaking in generalities there actually IS a wrong and a right side to this affair. It actually IS OK for people to be gay and the converse position is a mental disorder. Not all "preferences" are equally morally grounded and it does nobody any good to prop up mental disorders like religious conservatism as if they were normal acceptable positions.