Even if the "moral" society is doomed to fail and bring a horrible disaster tomorrow, you can still get fuzzies and social status for promoting it today.

On the other hand, it is also important to ask how much certaintly do you have that it is doomed, and what is your evidence. But in the real world, promoting the "moral" society would include actively destroying all such evidence. But also reversed stupidity is not intelligence, and just because someone is trying to destroy the evidence, we should not automatically conclude that the evidence was overwhelming. Also... it's complicated.