You should not have the right to force my labour for you, that is slavery.

They don't. The bakers chose to be bakers. They chose to offer a personalised cake making service. If they don't want to fall foul of the law then don't offer that service to anyone. Make 10 standard cakes and its fine. If the bakers are free to discriminate over who they serve based on skin colour, sexuality religion etc then I demand the freedom to put a brick through their window. Society only works if we follow rules designed to get us living peaceably alongside each other. You may think there's a difference between violence and discrimination but that's probably because you've never had the boot of discrimination pressed down upon your neck. Ultimately allowing discrimination to fester in society will always lead to violence as the oppressed try to fight back.