It has been a strategy of the left for a long time. Project you are winning, and you will. My friend told me his dad said that years ago. Of course we grow up watching sports ball, so being on the winning side is an ego thing too. He convinced his dad to vote Republican that year and explained all the reasons why. His dad voted republican, and the Democrats won the presidency that election. His dads response was "See, I wasted my vote, I should have voted Democrat and I would have been on the winning team". No one wants to say they were on the losing team, so when the fake news is covering the election, they like to hype up how the side they want to win is doing so well and a sure thing to win this election. They hope this will get more people to get on the winning team and vote for their candidate.
So if we project the winning team is team Trump, maybe we can get a few people voting for him and make sure it is a self fulfilling prophecy.