Well, should they?

Yes, they should.

If doctors are increasingly to become the authoritarians of our health, able to force us into treatment against our better judgment or will, then they have every responsibility to fully disclose to their patients any considerable biases that would influence their decision to push a line of treatment or medication.  If doctors are going to be entrusted with such great power - not just medically but legally - then they need to be held to the highest accountability for that power.