Dunno, this seems perfectly sensible to me. If a patient doesn't have much other information or expertise to go on, the decision they're making is as much "do I trust this doctor?" as it is "should I have surgery?". And setting aside the latter question, I don't think it's irrational for hearing a disclosure to influence the former.
Also, a doctor aware of biases may be more competent than one that's not. Conspicuously absent from the first post is any comment on the relative value of the doctors.
Dunno, this seems perfectly sensible to me. If a patient doesn't have much other information or expertise to go on, the decision they're making is as much "do I trust this doctor?" as it is "should I have surgery?". And setting aside the latter question, I don't think it's irrational for hearing a disclosure to influence the former.