Religious or personal beliefs have no place within a business.
If you’re not inciting criminal activity then I don’t think you should be able to deny in this case.
If they forced the baker to partake in gay marriage or come along to a protest on it, then fair enough, absolutely not.
But the bakers job is to bake and decorate cakes to the customers request, presumably he advertised that he can ‘add any message’ he’s not the moral police. If he can’t do his job, he shouldn’t work there.
I also think refusing the pill or abortion because of ‘religious beliefs’ if it’s in your job description to do so, shouldn’t be accepted.
Individuals have a right to say whatever they want, to not say whatever they want, to disagree with things and to agree with things.
When it comes to businesses you should not be able to discriminate or not fulfil requirements if they are within the remits of what your business provides.
If he wanted ‘say no to gay marriage’, I would still think the same, although I would think the person requesting it was a twat.
It is completely different to the ball waxing case. Those businesses did not provide a ball waxing service. They refused as they did not do this service, not because they didn’t like trans women, the bakers refused because they didn’t want to, despite providing this service.