I think that would come under the primary freedom outlined in the charter, which is freedom of conscience and religion. Freedom of expression comes in the second part of the fundamental freedom, so I would agree that they should not be coerced against their conscience in that case.
My concern here is actually more in professional associations where what a doctor, physician, nurse, pharmacist or whoever might say is being policed. It's not because of the professional competence of that medical practitioner, but because of the view that, in this case, the professional body might take. That power is given to them by the government, so they hold the livelihood of that professional in their hands.
In fact, in a way, a professional body has more power over it than maybe the provincial government, which has more blunt instruments. To limit your livelihood is a pretty powerful power given to regulatory professional bodies.
As well, when you seek redress against them, it's harder because courts give them more deference—because what they're supposed to be doing is professional regulation—than they would to the government if the government did the same thing.