First let me define devaluation as a defense mechanism to avoid ambiguity. An example would be say if you failed an exam and to avoid self criticism and frustration you came to the fallacious conclusion via compartmentalization that the subject was irrelevant in the real world or the test was unfairly structured. Basically if you can't get something you devalue its worth to avoid frustration etc.
I've noticed that Buddhists tend to do this a lot in regards to pleasures of the flesh. Whats the point in accumulating wealth if its all impermanent. It will only lead to a cycle of craving resulting in more suffering. To people in poor nations who watch the decadence of the Western world on their T.V.'s
So is it a truth, a defense mechanism or something in between?
MM: No question these teachings can be used as a convenient excuse, or as a "feel better about your lot in life" defense mechanism, and more often than not, are being used for exactly that.
That does not take away from the truth, though, that all wealth and pleasures of the flesh aka wives, husbands, children, knowledge, status, money, etc, are impermanent. Even our own body is impermanent.
What that means is that all things are therefore infinitely meaningless and infinitely precious - in this very moment in which they exist. Wealthy - poor - sitting in the dirt - in your own blood - on a golden thrown - or in a Ferrari - if you miss the moment, you simply miss. If you don't miss, you discover what Buddhism is trying to teach - the true end of suffering instead of a clever way to avoid suffering.
You bring up a good point, too. "Defense mechanism to avoid ambiguity" - the whole goal of Buddhism is a serene "don't know" attitude after a long dismantling of knowing. You'll have to forgive those in Buddhism who are still learning to unlearn to reach full ambiguity.