I think what bothers people today is that the spoken language, another species, almost another genus, from written language, is being written and shared in print. In the past, the spoken language was preserved almost exclusively by good writers who tried to transcribe what they heard. Mark Twain was legitimately proud of his re-creation of a variety of regional accents. Other writers lacked his genius. What resulted were hundreds of pages of incomprehensible dialect in print, which may or may not have been anywhere near to accurate. In consequence, people who spoke this way were looked down upon as a lower form of humanity, not struggling with a foreign tongue but literally (ha) stupid.
Teachers bought into this classism and racism. The accepted notion of a school was to “assimilate” the young, implicitly meaning that the standards of white, middle-to-upper class educated speakers and writers were reduced to rules that, like the bed of Procrustus, forced all English into a set of “acceptable” forms, i.e., acceptable to a judgemental elite.
English has no rules for usage. Grammatical agreement, yes, if a bit fuzzy at times. The use of apostrophes, yes. Spelling, mostly. But usage, no. You can end a sentence with a preposition. You can modify an absolute with an intensifier. You can dangle a participle. If you listen to spoken language, people do that all the time because normal minds don’t plan out the ends of a sentence before beginning one. Listeners will understand. Some confusion may result, and some mismatches may be comical, but we mostly get it. I’m far more concerned when here on the Dope a person writes a perfectly coherent sentence and a later poster twists it into an interpretation from Mars.
Today, everybody is able to set down their natural speech and rhythms in print. Those are seldom what got taught in school. Some of it sucks, sure, but so did a lot of formal, prestige writing that adhered to every rule. The good writers I referred to need to use their finely honed perceptions and sort through the avalanche of words to decide what to keep, what to toss, and what to live with for the ideas and feelings that are valuable if awkwardly displayed.
OTOH, some people are just plain stupid. Unfortunately, they aren’t all bad writers, so that’s not a tell.