And I agree with your argument--"gay" may be something that you are, but a "gay wedding" is something that you do. It's the doing part the baker would prefer not to participate in. 

We also don't need to chuck all the civil rights laws to accommodate religious beliefs. We can make exceptions to those laws, just as we make exceptions to "freedom of speech" laws--you can't false cry "fire" in a crowded theater and then claim free speech protection. I'm optimistic the SC will rule in the baker's favor, as it did in Hobby Lobby and other similar cases. Even bakers have constitutional rights that are not abridged when they open a business.