The enforcement of laws always comes down to the coercive power of the state, or some other government entity.  Would you actually agree with throwing someone in prison, or taking their property to enforce a fine, for not entering into an economic exchange with another (participating in their wedding).  A wedding cake is not just a cake, nor is any ring a wedding ring.  There is a high degree of significance attached to them; ask any married person, secular or devout.   Why would you want the bigot's cake at your wedding in the fist place?   

Regarding being pushy: "Even though you've declined, I DEMAND that you bake this cake for me.  If you don't, I'm calling my attorney!"    That comes across as pushy to me.