You know what my biggest problem with descriptivists precriptivists is? What is "correct" always coincides exactly to what they learned in school or university from 15 - 20. It's never anything else. Never in like 20.000 years of human history did we nail language except for that timeframe, and never will it happen again. what a coinkidink.
Much of the stuff people correct each other on is stuff we all were taught. It just didn't sink in for some.
Though there are outdated and incorrect ideas (eg "no split infinitives in English" was never correct, but was taught when boomers were in school, and later in less progressive places)
Prescriptivists you mean. Descriptivists describe language phenomena as they are without passing judgment on their validity whereas prescriptivists have certain assumptions on what constitutes parts of the language to be valid and prescribe meaning to them