While I don't think it's actually targeted demoralization propaganda, the idea that things must get worse before they can get better has come to serve the same purpose as demoralization propaganda. It lays out the notion that there's nothing we can do right now to fix things, that we must continue to endure these hardships until some undefined point in the future where some backlash will magically manifest. I reject this premise and posit that we have already reached and passed the point where the populace at large should have provided some sort of extreme rejection of the abuse it is being subjected to. If we continue to parrot the idea that "things must get worse", then things will only continue to get worse. It will continue for years, decades, generations, until the people enduring the abuse are those who never knew what came before and how much better things could be. The Soviet Union was a shitshow for decades; Is that the timeframe we want to entertain for how much worse things must get before they can get better?
It's all just an abdication of the responsibility to correct the situation ourselves.
"It must get worse before it gets better" is just a less precise way to say "for people to act, the pain of inaction has to exceed the pain of action."
It's not advice, it's not demoralization, it's just a fact that plays out daily in every aspect of our lives, from working out all the way to getting the boot on your neck.