Mostly it's that the USA has been obsessed with Russian even since the end of the Cold War, with literally no one in DOD thinking seriously about China as a threat. Very much like 1930s Japan to be honest.
Had Nazi Germany coordinated with Japan to focus on Russia, we would have lost. Japanese stretch too thin across Asia Pacific islands. They would have done much better had they establish their empire on eastern Russia while Germans chomping the west side. Russians wouldn't have the manpower to mount against Germans. Affectively resulting in Germans and Japanese having a huge contigous defensible territory shielded from even nuclear bombs. Then within 5 years, they would have build enough atomic bombs and V2 rockets to wipe USA. Essentially alternate universe that Philip written in The Man in the High Castle. I'm glad I am in this universe, not Philip's. So Russia basically saved USA indirectly. The irony we treat them as the worst bad guy ever.
