Why shouldn't a customer expect the service that the business owner advertises that he provides? What's unreasonable to expect the business owner to live up to his word? Religion is a bullshit excuse for arbitrary discrimination in this situation.
Actually IMO it's the other way around. It's the govt trying to enforce it's religion arbitrarily on the business owner, in this case leftists forcing the ideology as policy down the throats of owners based on unelected tribunals of bureaucrats decreeing that this group or that groups is now 'protected'. Often times at odd with existing law or even facts itself.
Transgenders are the perfect example. There is ZERO facts, zero science, or anything real whatsoever about someone declaring themselves to be a different sex by 'identifying' as that sex. Yet not only are businesses supposed to recognize that, in places like New York their supposed to correctly call them by their proper pronoun for all 40+ recognized genders, as I stated earlier. None of this is anything but twisting the existing law to fit the liberal agenda, as the law does not read any accommodation for gender.
And they are trying to expand the definition of 'public accommodation' to clubs, churches, and just about anything that isn't protected by armed guards and 'keep out' signs, regardless if they sell on dime's worth of stuff or not. They're doing that right now here in Iowa.
And not only do they force business owners to serve any of their protected groups, they attempt to give these groups near unlimited rights to receive any service they desire. Fortunately the courts have limited some of that. Yet these same unelected bodies, like in Colorado, refuse to punish a gay bakery when their customer requests something they don't like.
That is what I call arbitrary. Very little of this is being driven by anything but a cult like devotion to a very one-sided religion masquerading as ideology and being passed off as policy.