They aren't actually demoralized though, that was the Soviet government's mistake.
They may have thought that they were destroying a populace's free will but all they really did was make them afraid to speak out, or even share a taboo opinion with a friend.
Russia escaped a serious revolution through Glastnost and greater accountability but to see the real results of "demoralized people" you have to look at Romania as they practiced Soviet techniques to the extreme.
We all know what happened to Ceaucescu.
It isn't that demoralised people can't reason. They can reason but it's so scary for them to have a forbidden thought, much less express it that massive cognitive dissonance occurs and that all comes to a boil in the end.