There's a sense in which even doctored polls can become (or contribute to) self-fulfilling prophecies, though. The key tactic of disinformation is to bombard the viewer with so many semi-legitimate sources that they have no time to consider each one on its merits; by the time you've seen that the "independent institution/pollster" is owned by someone with ties to X, you've already been hit by five other polls and think-pieces saying the same thing. At the end of the day, you invite the thought "is there actually a zeitgeist here, am I the one behind the times if I'm questioning what everyone else is saying" - and at that point, you're susceptible to propaganda. We should not discount Putin's purposefulness and confidence in deploying these tactics.