It's not a lie. You're misunderstanding the intent, the mechanism of action, and the effect.
People read articles that align with their predetermined narrative more than they read articles that contradict it. Which means that they are completely ready to believe that Trump sold secrets to Russia or whatever, and they go into the article believing it already. Believing that the news is possible, and even likely.
If the article is about Hillary selling secrets to Russia, they will say to themselves, "no way, that's crazy talk" and move on.
But if they go into the article believing it, and THEN find out that the person in the article is the opposite of who they thought it was, they're left with cognitive dissonance: they already believe the allegation, but now they have to wind it back, to exert effort and UNbelieve it. This causes mental anguish, and sooner or later they will recognize that the cause of their mental anguish is their own bias.
And this destroys the bias.