An unjust law is not a law. If I sell cakes I myself will surely refuse to make a wedding cake for lesbians, sodomites, and other sexual pervert people.
I agree with you. Law should be equal for everyone. Imagine what will happen, if you go to a bakery run by the African Americans and order a Confederate flag cake. Or imagine what will happen if you go to a bakery run by homosexuals, and order a cake with the label
"Death to the Sodomites". If bakers can refuse confederate cake, then for sure they have the right to refuse a Lesbian cake.