Note: I don’t necessarily agree with every point every author listed here makes.
The largest and most famous such experiment was conducted in the Soviet Union, and it failed miserably. ‘Everyone would work according to their abilities, and receive according to their needs’ turned out in practice into ‘everyone would work as little as they can get away with, and receive as much as they could grab’.
Political correctness is communist propaganda writ small. In my study of communist societies, I came to the conclusion that the purpose of communist propaganda was not to persuade or convince, not to inform, but to humiliate; and therefore, the less it corresponded to reality the better. When people are forced to remain silent when they are being told the most obvious lies, or even worse when they are forced to repeat the lies themselves, they lose once and for all their sense of probity. To assent to obvious lies is in some small way to become evil oneself. One’s standing to resist anything is thus eroded, and even destroyed. A society of emasculated liars is easy to control. I think if you examine political correctness, it has the same effect and is intended to.
When every benefit received is a right, there is no place for good manners, let alone for gratitude.