Ugh.
A gay cake maker is does not have to make a cake condemning homosexuality as that would be political. Political thought is not protected. If the cakemaker had said he would not make a cake for the couple because they were Democrats, he would be fine. That is not a good example.

If you offer a service to the public, you must offer it to all.
According to Colorado law, he may as well have refused to bake a cake for white people.
Would that bother you?