Except the facts are even worse for the baker. The Brief in Opposition, as noted above, describes the refusal of service as rooted in the baker's animosity toward same-sex weddings; he never questioned the customer regarding the "artistry" to be deployed on the cake. Even an off the shelf cake, it appears, would have been verboten.
According to an affidavit filed with the Brief in Opposition, another customer sought cupcakes for a same-sex commitment ceremony. Not an artistic wedding cake, but cupcakes. Not a wedding, but merely a commitment ceremony. And the baker refused service. The more I read into this case, the more I can see why the SCOTUS took it. This is going to be no great victory for the baker. His conduct was bigoted and deplorable, and I expect the Court to uphold the efficacy of the community's laws against arbitrary discrimination.
But all your supporting arguments here are based on morality, by assigning moral epithets to the bakers actions based on vague and nebulous suspicions of his state of mind, and you are using it to dance around the issue with it.
If we have separation of church and state then it applies both directions. We don't base legal decisions of moral epithets. Even the administrative law judge ruled with a coulda-shoulda-woulda ruling that the baker was supposed to know the state of mind of the gay couple, who
may have wanted a nondescript cake. Yet the judge ignored the fact that if their cake was so nondescript then they could have gotten it off the shelf.
Cupcakes are no different. If they wanted anything but off the shelf cupcakes then they were asking the baker to use his talents and creativity to make something specifically for them. That's commandeering someone's effort and creativity to cater to your morality.
Which highlights the real issue here - this is really a case of a gay couple trying to make their morality dominant over another's morality via the courts, which is a violation of separation of church and state and the 14th amendment. They simply disguise that by calling it bigotry.
It becomes even more ludicrous if it had happened to be two transsexuals, who's status is entirely belief based.