You're seriously overthinking this. Descriptivism isn't some plot to twist our cherished language, it just describes the language as it is currently used by speakers.
I believe there needs to be serious limits on the ability of “descriptivists” to condone divergent meanings of words. Within reason it is fine to describe new slightly expanded uses of words but wholesale accepting that word meanings can change arbitrarily in principle seems harmful to the maintenance of the integrity and quality of our language. For example, many people dislike HOAs but neighborhoods with HOAs maintain a certain level of quality, while neighborhoods without HOAs have quality levels across the board, including very bad.