It's too convoluted. Is the problem religious freedom, or freedom of artistic expression?
It almost seems that religion can be a defense of refusal, only if there is artistic expression involved. However any business could claim that they use artistic talent. Pizza makers, cabinet makers, baristas, and even plumbers who make make artistic solder joints or perform a special dance with the sewer rooter. 
Or is it that no business can refuse service to anybody for any reason?