During my psychotherapy training one tutor had particularly contraversial views. Because his own psyche was polarised he interpreted the world and others in this way. His damaged ego was unable to take responsibility for mistakes.
This conversation never happened. When he taught the class that polarisation is a given, he shouted out examples for the class to respond in unison. When he shouted 'black' there was a loud chorus of 'white', while I thought to myself (realising from past interactions that challenging this person was dangerous), I thought 'grey' though kept it to myself.
I went on to study Gestalt (I left this course at the end of the year) which does address polarisation. If you are polarised and you see a gestalt therapist you probably would not be by the end. You may experience each pole though find a capacity for fluid movement between the two which is healthy in the mind and the universe as a whole. Freidlander described the beautiful phenomenon of creative indifference (the mid-point between two poles) which help us understand this occurance better.
Ridgid thinking of this kind can be addressed in Therapy through an attitude of creative indifference (no need investment in either pole whilst holding both) of a good therapist. The strong ego of this person is defended (instead of addressing his incongruent statement he deflects the issues onto the other person). Narcissism often occurs because of a lack of mirroring which to a degree can be addressed in Therapy.
If your therapist seems polarised, overly ridgid, unable to dialogue (you shut down instead of speaking your mind) or narcissistic I would walk away.