Evil doesn't sell. Therefore, if you set out to do evil, you distort the language in order to deceive -- to make it sound as if you're doing good. You can give good names to horrible things ("choice," for instance). Or, you can talk up some little bit of good while keeping silent about the larger evils. It IS depressing. A very old trick, observed and told by many writers and thinkers before us. Old? Cain tried to deceive God about slaying Abel!
The antidote -- my favorite, at least -- is to cut through the euphemisms and describe things in plain, honest words. Then there is no place for evil to hide.
In my observation often the greatest lies are those wrapped around a core of truth, sometimes mostly true, almost true, but with a barely noticeable taint of lie. Our minds seek to go to the core, see the greater truth, and gloss over the tiny lie which obviates the truth.
Concomitant to that is for the liar to weave a lie bundled in threads of euphemisms as you mention so the recipient is not quite sure what was heard. Yes, simple words and simple truths are the antidote.