I believe the vast majority of people in the west believe that the west, despite some fixable issues, represents the Good, whereas for instance Nazi Germany or Stalinist Russia are the worst Evil Nations ever created, while when one stick to the facts it's much harder to tell them apart (but for the fact that one side won and therefore can tell its own story).

This observation alone leads me to believe that there is some very effective propaganda that's been going on for a good while.

Impossible to find out for sure of course, as the only propaganda that is visible is the propaganda that fails.