I feel like this is already been litigated. Anyone can refuse to do anything due to their personal beliefs, but they can't actually stop people from getting the service from someone else.
And I do believe you actually have to have already made the objection prior to your employment, otherwise you're now refusing to do part of your job.
I'm convinced that's exactly what they want. Or at least, they think that's what they want, I am ll doubtful that a great deal of thought has actually being put into it.
If it actually happened they would be complaining within about 3 days about the lack of food on the shelves and the lack of fuel in gas stations.