What about a pharmacist who owns the pharmacy?
Exactly, if they own the business, they should be able to do whatever they want. In the end, they are the ones who face the consequence of their actions. A pharmacist who refuses and gets fired, can find another job. A business owner stands to lose their business, and their investment in that business.
At that point I think it's pure business. He can decide not to stock any drug he doesn't agree with. He'll lose business accordingly, but that's his problem.