In an ideal world, this gay couple would have found someone else to make the cake. In an ideal world, simple word-of-mouth that a given business refused to cater to non-christians would be sufficient for non-christians and christians alike to decide whether or not to be a patron or client. We do not live in such a world. Tell me, what message does this tell the world about christians? What message does it tell non believers about Christianity? What does it tell non-believers about the character of Christ? If you are saved, if you have the capital T Truth, act like it.
This artist was "targeted" by the pro-gay agenda. You are right, they could have bought a cake somewhere else, but that was not the plan. For all of your words, Jesus still condemned the behavior, but not the person. Read again the account my friend. THAT is the POINT!