Among other reasons, what do you do when people start inventing religions to get out of doing things they don't want to? Should the government be in the position of deciding which religions are "real"? Just look at the history of Scientology or modern Satanism for examples.
For me this issue is so frustrating because in the gospels, Jesus repeatedly went out of his way to accept and bless society's cast-offs. He tells his followers to turn the other cheek and be wary of imposing judgment.
Yet today, people who supposedly follow his teachings are eager to do the casting off themselves, based on a few sketchy line readings from elsewhere in the Bible. I just don't understand how someone can read the New Testament and come away with "be mean to gay people" as a priority message.
Perhaps more importantly, the difference between that and a landlord "offering service"?
We talk about the wedding cakes and the photographs, but it's important to remember that less than 50 years ago, blacks were constantly turned away from houses in nice neighborhoods for similar objections.
Folks who fought for Jim Crow laws did not view themselves as willfully evil people who discriminated for no reason. They viewed their own support of segregation as a principled moral stance. That's why they fought so hard.