There is nothing in any of the "gay wedding cake" cases that indicate that the gay couple ever wanted anything on it other than what the baker did for straight couples.  There was no discussion on how the cake was to be decorated in either the Masterpiece Cakeshop, or the Sweet Cakes by Melissa cases.  It was simply them finding out that the cake was for a gay wedding, and refusing them right then and there.  Let me put it this way, by asking you this question: if this couple has said, "Fine, we'll take a straight wedding cake, and just use that for our gay wedding" do you think that Jack Phillips would have said, "Fine, I'll bake you one of those."?  Or do you think that the very fact that one of his cakes was being used for a gay wedding is what he objected to?

The baker is free, for instance, to not stock same-sex wedding toppers.  Not all wedding cakes have cake toppers.  There is no indication that the couple even wanted their cake decorated with a wedding topper.