Superficial reason is the creation of an external enemy. This is a multi-functional ploy. It diverts the masses from focusing on their individual problems, such as poverty,and a general sense of disempowerment; as in "hey, I got problems, but my biggest fear is the Russians are gonna nuke my country."

Another reason is that Russia, via RT and Sputnik news media, focuses on the detachment from reality of the entire US foreign policy, and our domestic police state. They don't want you to think about that. This is necessary in order to proliferate the grand illusion that the US is bygod the last bastion of Freedom on the planet.
(Bend over and let me grope your genitals to make sure you're not an underwear bomber).

But the overall major reason for demonizing Russia is that there can be no New World Order, in the fullest sense, as long as a major nuclear power stands in opposition to their goal.

Raye wrote about this years ago, that a New Cold War was necessary to stymie the plans of the NWO.

You can tell by the news of massive pedophile exposure and by the verbal gyrations of Admiral Kirby the marble-mouthed State Department spokesman when talking about RT as disinfo agent, or the bombing of children and hospitals in Aleppo, by the (pick one) Russian or Syrian air force.

If all this seems obvious to you, congratulations for seeing through the sham. The obvious nature of the hoax is evidence that these are last-ditch efforts to perpetuate the illusion that They are still in power.
Really? Jeezmobeez, they couldn't even predict that Trump would win the election.

They are done. They just cannot accept that yet.

But that's their problem.

Don't make it yours.