He's not. Selling a cake isn't supporting gay marriage.<quoted text>
Why is he being force by government to support gay marriage with his talents?
If McDonalds sells a guy a couple hamburgers and he takes one to his mistress, is McDonalds supporting an affair?
If a gun shop sells a woman a gun and a few months later, she shoots someone, is the gun shop supporting murder?
If Home Depot sells some fertilizer and someone makes a bomb out of it, does Home Depot support terrorism?
Selling a cake is selling a cake. That's it.