After one of my performances at a storytelling festival, a couple came up to say they enjoyed my stories. It is important to note that I tell many of them in the vernacular of my native Ozarks. The woman simply complimented me, but her husband tempered his compliments by saying, "I can't get over how you have a Ph.D. in English, and yet you butcher the language that way."
I said, "Oh no, I don't butcher it, I just slap it around a little. Got to show it who's boss."
His culture had taught him which usages were "good," implicitly tagging the rest "bad." Though culture supplied the details. I don't think it had to teach him the principle. There are good empirical and theoretical reasons to conclude that a tendency to adopt and try to enforce linguistic conformity stems from the same source that gives rise to humans' innate language capacity—our evolutionary heritage.
You may be able to find some empirical evidence inside your own head. Even if you have now developed the same level of usage tolerance as our editor, don't you recall times when you have thought something like, "Now, why would so-and-so call a bedstead a bedframe? Doesn't she know the right word?" If you're a Northerner, haven't you thought, "I just don't see how Southerners can make two syllables out of the word that"? Or if a Southerner, "Those people up north clip their words off too short"? Even though I try to be a principled tolerator, I still sometimes find myself wishing folks from the lower Hudson Valley could see their way clear to pronounce the vowel in dog and fawn some other way. Nobody ever taught me to disparage the pronunciation. I liked the classmate I first heard it from, so my feeling cannot be explained as personal antipathy transferred to an innocent diphthong. It just welled up.
Also, the tendency appears too early in a child's development to be readily explained as being a result of culture. My son learned his English here in Wisconsin, modeling at least as much on his day-care providers and playmates and on his older sister as on my wife and me. When he was about two, before he could differentiate between /f/ and /p/, he could already consistently pronounce /aI/ before /r/. I don't. I would lead him to our wood stove and say, "Ward, come help me stir the fahr."
He would look up indignantly and correct me with "No, pye-er!"
I am happy to report he soon learned /f/, and by age four he could not only tolerate my pronunciation but articulate it as well, when he chose...