Perhaps they're wise. Nowadays, many kids can barely spell. I think spelling and grammar are important for good and clear communication. However, I think that one should not be excessively prescriptive about the language. Too much emphasis on all this will stultify language.
Some grammar can help people understand why they are saying what they are saying.
Good spelling avoids ambiguity. However, too much of it is inevitably going to turn people off, bore them, make English something that they dislike and do not regard highly, and frankly they'll do what they want to do anyway. So the answer is for me, a bit of both. I think accent is often a question of perception. That said, it is true that communities which are very closed and self-supporting, traditionally tend to evolve a very narrow and shared form of speech.