Common rules for spelling make sense (though English really needs to stop using 16th century spelling because it stopped making sense ages ago), but for things like word use, prescribing what words to use is plain snobbery. A lot of it comes from “this is how I speak so this is how you must speak” and “this is how Latin and Greek do it, Latin and Greek are Very Cool Languages, so we must do it too”. “Never end your sentence in a proposition”, “use fewer instead of less”, it’s all bullshit.

Spelling is just a way to make exchanging text easier, but nobody gets to decide what words you and your community use. Some English dialects still use (forms of) “thou” even though most English speakers have switched to the formal “you” (compare French tu/vous, German du/sie) and that’s just as valid as any other dialect. Language is malleable and while having a common tongue is useful, anyone trying to rule over the language you speak with your peers is just power tripping. This also applies to AAVE, by the way.