We can't say efforts by any outside operatives caused Clinton to lose the election (those on the Right, please note my fair assessment). It is not like a bat hitting a ball and the ball goes flying. We can only question what would have happened.
From my perspective, the DNC usurped the primary (which is really a club president election, not a democratic election) by manipulating it so that Hillary had an easier hill to climb than Sanders. Criticize Sanders all you will, the evidence of the bias within the DNC (which they denied) came in their emails.
Debbie Wasserman was the worst of the party. The party neglected the needs of many poor people, catering to the rich in the form of people like George Clooney. Then to have Donna Brazille lie about leaking questions to Hillary was another nail in the coffin.
Can't say Sanders would have won, but he had no dirt in his history.  Yet an old socialist Jew was able to give Clinton a run for her money. That should have given pause.