As he pointed out quite correctly, MPs are representatives -- charged with serving what they believe to be the best interests of their constituents, and to use their judgement, whatever that may be -- and *not* delegates, mere mouthpieces of the country, or the party, whose only role is to walk through the door they are told with no thought.
A polarising Speaker, I have no doubt -- but, in the end, his job was to help strengthen Parliament, and to allow it to express its will. In that regard he has been successful, and he is but a scapegoat for Brexit supporters -- after all, for good or ill, Parliament's will right now is to reject a No Deal Brexit, and has been to reject the Withdrawal Agreement.
Funnily enough, the Speaker came to the aid of Hard Brexit supporters in that regard, as he tried to block Theresa May from constantly bringing the same (or virtually the same) deal back time and again, as was her earlier plan.