In my view, this brief strikes the right balance. It recognizes that even businesses have First Amendment protections against compelled speech. Thus, if Phillips had been asked to customize a cake with a pro-gay message that he objected to, he would have a stronger claim. So too would a photographer or a singer who refused to participate in a same-sex wedding because photography and singing, unlike cake-making, are inherently expressive. But merely making a cake is not expressive, so it is not protected speech under the First Amendment.
This blog reflects the views solely of its author. It is not intended, and should not be regarded, as legal advice on how to analyze any particular set of facts.