Remember, we didn't beat the fascists during WWII using arguments and polite discussion. We bashed the fash back then, we can and must bash the fash today.
They surely did their part, but it wasn't only them. USA also had a quite important role in it. Yeah, the USSR won Stalingrad and pushed the German force back, but after the USA landed in the Normandy Germany had to fight at 2 fronts, which reduced the amount of casualties on the allied sides. Would the USSR be able to win the war without the USA? Maybe, I seriously don't know, but saying that they were the one winning the war is kind of ignorant.
Would the USSR be able to win the war without the USA?
FWIW Kruschev said no fucking way, despite later claims of the Soviet leadership to have not needed US support. US-supplied weapons weren't very important, but US food and trucks and petroleum allowed Soviet industry to focus primarily on weapons production.