It's similarly true about Soviet propaganda. The people living in Soviet territory commonly believed the propaganda about the US and West as well. Even the highest tiers, including eg Yeltsin, believed some of the false propaganda (which is why Yeltsin couldn't believe his now famous 1989 visit to Randall's grocery store in Houston Texas wasn't wholly staged). Yeltsin was on record admitting that even the upper echelons of Soviet power believed a lot of the false propaganda they were fed.

You can still see a river of false propaganda common among the Russian people in their beliefs about the US. It's all over YouTube in interviews-on-the-street type videos. The Russian people still live under a totalitarian regime that directly controls all media, all democratic actions and tries to control all information.

But escapees also have an incentive to lie. Nobody will hire them, assuming they're spies.

The only real employment they can get is giving interviews about how awful and insane North Korea is.

That's not to say it isn't, of course.