From here, the Indian social reformer B. R. Ambedkar is supposed to have said:
In the Hindu religion, one can[not] have freedom of speech. A Hindu must surrender his freedom of speech. He must act according to the Vedas. If the Vedas do not support the actions, instructions must be sought from the Smritis, and if the Smritis fail to provide any such instructions, he must follow in the footsteps of the great men. He is not supposed to reason. Hence, so long as you are in the Hindu religion, you cannot expect to have freedom of thought.
Is the quote authentic? Did he say this in a speech or in one of his books?