When people use words as defined in the dictionary then it is still descriptive though.
If you mean people can use words as defined in dictionaries and those dictionaries are still descriptive then I agree.
Apart from my disagreement on this point voiced above, in that case people should change the dictionary. They haven’t. If everybody uses their own definition then language becomes useless.
A dictionary that uses a descriptive approach very well might. It doesn't matter if the dictionaries haven't. As long as people understand each other when they speak it's fine. People can understand meanings of words even if they aren't all enumerated in the dictionary. This is self evident from observing any number of conversations on or off line. The one example that comes to mind is the use of the word literally. People used it incorrectly, for when they meant figuratively. The response people gave was not, I do not understand what you said. They said you didn't mean literally you meant figuratively.
And on Merriam-Webster's website, they did add a new definition to the literally based on its new usage.
2
: in effect : virtually
—used in an exaggerated way to emphasize a statement or description that is not literally true or possible
will literally turn the world upside down to combat cruelty or injustice—
Norman Cousins
The comment I replied to originally was using the word sarcasm to mean he doesn't mean what he says. So that's the definition I used in my reply. I understood what the writer of the commenter said without needing to refer to the dictionary first. As I said, his tone of voice certainly sounds sarcastic and seems to meet the definitions you listed. This isn't particular relevant though. Fascists use the cloak of possibly plausible deniability to mask what they say. A sarcastic tone of voice is one such tool.
He doesn’t mean it, according to his own way of thinking at least. By our way of thinking he wants to destroy democracy, but not by his. That is why I’m saying he is being sarcastic.
I would say his characterization of US democracy, all the things he said the Democrats are doing in his joke, is his way of explaining why he doesn't value US democracy and therefore is why he is ok with destroying it. Based on the fact he doesn't like immigration or mail in voting, what he doesn't like about US democracy is that his minority doesn't fully control it. In his mind, both of those things deplete his minority's power. His speech does not indicate he values some other definition of democracy. When he says new American republic he means christofascist dictatorship. He knowingly wants to replace US democracy with a christofascist dictatorship, because then his minority will have total control over American life.
So nowhere in his line of thinking is he being sarcastic, as in he doesn't really mean it, because he doesn't value majority rule. He wants minority rule. He does not believe democracy means or is minority rule. Instead he believes democracy means and is majority rule and believes that is a bad thing. When the only real difference between our definitions is that we believe majority rule is good and he believes it's bad, we're all not only talking about the same thing, but we also all know the thing he wants to destroy is US democracy. edit: typo