I believe language plays a significant role in human psychology. Some words are "scarier" than others, I am sure there is a psychological benefit to using euphemism, these propaganda guys are clever, they don't do things for no reason. George Carlin was simply calling them out, he saw through the psychological manipulation.
It's enforcing an equivalence, subconsciously or not, through synonymous words.
For example if we create new terms for homosexual:
rainbow dancer
pit digger
The former is associated with
lighter or
happier terms whereas the latter bends slightly towards negativity.
I believe what happens, though, is there is a cultural push toward a certain connotation (given the most common tone/inflections) for given words. The "less abrasive" language nowadays seems that way because they were not yet given the overarching negative connotation but were pressed to initially seem positive.
That's why it's really never colloquial language that's used: to obfuscate any cynicism and to reset the tone to 0 so that it can be morphed into that of a softer connotation.
