Personally I think it's dumb for a business to turn down a paying customer, as the whole point of running a business is to make money. Unless it was something outrageous like a Hitler cake or something
But people speak with their wallets so I feel like if the bakery doesn't want to bake the cake then there's probably another bakery that will accommodate them and people can also choose to boycott their business because that's how the free market works
To some, making a Hitler cake would be likened to making a pornographic cake, or a cake knowing it will be used for sinful event. Some people truly believe the most loving thing they can do is to show others the errors of their ways, so they can turn from their sin, Is it right? Eh not my job to say. I iwll say right or wrong, I find it a bit irritating, however.