Re: Eight Day Apatheist
I'd gladly write "God hates fags" on a cake if cake writing was my job; it's just a fucking CAKE, not a binding endorsement of someone's ideology.
I'd suggest that if you don't want to write things on cakes that you don't agree with to get out of the writing-on-cakes business or only offer a set selection of generic wishes.
PS: Please don't bring up UK law when arguing on this matter; those laws haven't applied here since July 4th, 1776.