"Good" grammar is socially acceptable grammar. And people certainly do care about social acceptability, at least for other people. There was a big flap in the 80s {sic} about teaching subjects in Oakland, CA, schools using Ebonics, the dialect of many of the school children. Critics were livid about not teaching "correct" English and encouraging ignorance. The Oakland School Board mounted a silly defense. But it seems to me that if you are teaching arithmetic to a child who says twice as less instead of half as much, why not speak to him in his own language? Why make your task more difficult?
It is common in the U. S. for standardized tests to include questions of the form, A is to B as C is to <blank> . Minority children do not usually do so well on such questions. However, research going back to the 50s or 60s shows that the difference in performance between minority kids and others disappears when the questions are of the form, A goes with B like C goes with <blank> . One might think that the test makers would switch to the latter form. But no! After all, what is the point of the test? The latter form is socially unacceptable.
I think there's quite a lot questionable with this, Bill. It's almost as if you want to be prosecutor, defence, judge and jury, which is of course a good way to win a case. But the proponents of "good" grammar may not have been saying (or intending) what you say they said at all. For example, perhaps they regarded good grammar not so much as "socially acceptable" as "socially useful " or "economically desirable" - or even "economically essential". Maybe, heaven forfend, they even had the kids' interests more at heart rather than a love of grammar.
As to teaching in Ebonics, I view that through my own experience. When I was young, my native dialect was very different from standard English, probably as much as Ebonics is different from standard American (it's all changed now, though). At primary school we were taught by teachers who didn't try to make us dialect kids change our way of speaking, or at least not directly. They spoke to us in a sort of halfway house language - standard English with a local accent and local idioms. There were also middle class kids who spoke in rather the same way, but they also understood the working class kids. But at that level language wasn't a major issue, and certainly not a class issue.
It changed when I went to grammar school (age 11). There, most of the teachers were graduates from other parts of the country, teaching specialist subjects. They just couldn't understand people like me. I still remember scenes where a history teacher had to get one of the middle-class kids to interpret for me whenever I answered one of his questions. What I never understood was how he couldn't understand me but I could understand him. We didn't have tv in those days and most radio I listened to was in the local dialect, so I had no strong outside influences - I assume I picked things up from the posh kids, or maybe kids are just more flexible.
I don't think that my experience harmed me, so to that extent I wouldn't object to some teaching in Ebonics. But if I'd had to wait for a dialect speaker at grammar school level, I would never have got a higher education. People like me had to adapt to the teaching available. I don't recall anyone ever thinking that was an imposition or a hardship, so I have to conclude that asking Ebonics speakers also to adapt (at some age or other) is perfectly reasonable. There may even be an argument that says the sooner the better. I would imagine that there may be among our readers some older Germans or Italians, whose regional languages used to be very different, who have had a similar experience. Maybe modern Norwegians still have similar problems with bokmal and nynorsk. At any rate, I'm sure it's not just a black/white/Latino issue, an assumption which tends to charge debates with an unhealthy air.
As to the "A is to" as opposed "A goes with" business, I'm not sure that that is a grammar thing at all. It sounds to me more like people with a maths background assuming or insisting that we all have to think like them, which, as you well know, is an old but still buzzing bee in my bonnet.