Yes, people shouldn't be denied service because of their sexual orientation. I know this is just a birthday cake, but there are some towns that only really have one market for the whole town. If that market was allowed to refuse service to gays, it could force them into becoming subsistence farmers or travel long distances just to buy food! That would be crazy.
Basically this.
Using religion to justify discrimination is disgusting. If history and the current trajectory of this country are to be trusted, this bs will be banned eventually and these assholes will have nothing to fall back on.