That's the problem the way I see it. If a bakery can be sued for not making a wedding cake for a gay marriage, where is the line afterwards?
I don't think anybody should be forced to take a job they don't want to do. For instance on several occasions, I called out professionals to do various work for me. They came out, took measurements or whatever and gave me an estimate, but when I called them back to have them do the job, they never returned my call.
I don't think I should have the right to sue them because they didn't like the job. They wasted my time or the time of others who were here to give them access to look things over. If you don't want to do the job, screw you, there are plenty of people that want my money. I'll never call you again or refer you to anybody else I know.
While you don't have the ability to sue those people because they didn't take the job, if you have clear proof that they discriminated against you, you do.
Nobody in my opinion is forcing those bakers to be bakers. They can choose any job they want, just follow the legal laws to perform the task. Just like nobody would ever force a Christian who doesn't believe in premarital sex to be a porn star. If your belief is that under no circumstance would you ever take a life, nobody is forcing you to become a police officer.