I see the use of the Mother's or Sri Aurobindo's quotation in this regard as entirely illegitimate and highly dangerous if made into a collective judgment in sadhana. A spiritual teacher's words are uttered in a context of time, place, circumstance and receipient's personality, as a force in action not as a law for the ignorant to use as a substitute for truth.
Neither Sri Aurobindo nor the Mother were automatons who would respond with the same words for all time. Unless one has identity in consciousness with them, one cannot assert their authority on the basis of words written or said in a certain context in the past. Apart from their own changes of perception, both Mother and Sri Aurobindo have spoken in several places of the fact that the external and internal conditions of the environment in question do not remain the same and actions have to deal with the circumstances of the present.
The words of the past are a help only to the person who is called upon to act. S/he should ponder these words, but his/her action can only be a will directed from within and a living choice. Moreover, the proper use of these words are in personal growth and action, their use by others to dictate behavior in general or in specific cases is an instance of the abuse known as religion.
Can one be sure that the Mother has not herself put the author in the place and time and given him the preparation needed to do excatly what he has done for her work? DB Reply Science, Culture and Integral Yoga
Guruvada is a concept alien to the western mind and, on the surface, repugnant to its democratic ideal. I agree that more effort is needed to explain the mystical basis of guruvada to the western mind. Sri Aurobindo has some luminous explanations for guruvada.
On the issue of the place of devotion vs. the mind in the Integral Yoga, I would like to quote this passage from P's book, which gives a historical perspective to these things:
Mind is, as he said often in The Life Divine, "an instrument of Ignorance," not of knowledge. The seeker has to rise through mind "into some kind of fusing union with the supramental and build up in himself a level of supermind." This is what he had done in his own practice and he thought at first that others could follow his example. Some tried, but lacking his experience and balance, they could not repeat his success. Eventually he realized that the transformation he envisaged would be difficult if not impossible for others without a preliminary awakening of the psychic being, a development of such qualities as sincerity, devotion, and inner discrimination. To bring about this awakening was the primary aim of the sadhana under the Mother's guidance. (pg. 358) DB Reply Science, Culture and Integral Yoga