The article has a terrible slant to it. The case is not about a “license to discriminate,” and there are not “longstanding” legal doctrines against appeals from compelled speech. The case tests whether a state can in fact compel a person to engage in a creative production (“speech”) favoring something he finds abhorrent.
The major issue is this: will the First Amendment stand or not? It is a First Amendment case on two grounds. First, the baker’s objections are faith-based (the petition pretty clearly establishes his religious bone fides), making this a case about the free exercise of religion. Second, Colorado is seeking to compel a particular message, which is a violation of freedom of speech.
Keep in mind that the baker never refused to serve gays. This isn’t about some sort of Jim Crow behavior. He offered to provide the couple with any other product; he just would not create a wedding cake for them. I don’t agree with his stance on same-sex marriage, and I don’t share his religion, but that’s neither here nor there. He didn’t stand in the way of their wedding. He didn’t organize against them. The couple in fact had no trouble getting a gay-themed wedding cake from another baker. This baker didn’t do anything but opt out from expressing public approval of their wedding by virtue of designing and building a one-of-a-kind cake for them. For this the state of Colorado bullies him. That’s is the sort of thing one expects from totalitarian regimes, not a government in the United States.