Few reasons:

Many shrinks went to the field to solve their own problems.

Medical model. What do you expected from a person who believes in this model? I mean the whole "I am normal, you have a broken brain..." cannot result in decent interraction.

And from I see on MH communities... some shrinks are ****ing dense. The way they dismiss complains of their clients, all the power plays... I am not sure where the "trust your doctor" **** comes from. Probably from the doctors who cannot earn trust by authority or wisdom....