Cake baking and freedom of speech

A take that I think is right but which I have not seen expressed before.

Keith Burgess-Jackson points out that the controversy over whether commercial establishments can and should be forced to service patrons whose actions contravene the business owner's religious beliefs is not only about freedom of religion.

There's more at stake than freedom of religion. There's also freedom of expression. If I am required by law to affirm something I disbelieve, my First Amendment right is violated. Freedom of expression includes freedom not to be made to express. Let's apply this idea to the case of homosexual "marriage." If I bake and decorate wedding cakes for a living, then I may not be forced to express, either in, on, or though the cake, views I reject (for whatever reason, including reasons of religious conviction). The same is true of photographers, painters, and caterers, all of whom express themselves through their work.

I think his argument is fundamentally right but what is striking to me is that there has been a national conversation on this case for a couple of months now and all the focus has been on religious freedom and, as far as I know, no one has focused on the freedom of speech issue.