I think the important point is the utility of language, not its "correctness". Regardless of the political issues involved, speaking the "standard" language or the prestige language is an asset in most circumstances.
Speaking Ebonics would make it harder for a doctor to win patient trust, harder for an interviewee to get a job, harder for a politician to win in most districts and even harder for a defendant to get a favorable judgment. Any teacher who ignores this fact does a disservice to the students.
Probably true, but irrelevant to the article, which is about how more effectively to teach Standard English by recognizing that some students start from a different dialect.
I don't think that's what the article was about at all. The article was essentially an attack on press coverage the author wasn't happy with. Its focus was more political than pedagogical.
From the article:
"Yet opinion writers proceeded to fall upon the topic like starving dogs attacking a bone. They ridiculed, they sneered, they frothed, they flamed, they raged, they lived off the story for weeks."
This kind of language just doesn't show up in secondary education guides. It's clearly about demonizing the opposition.
Speaking Ebonics would make it harder for a doctor to win patient trust, harder for an interviewee to get a job, harder for a politician to win in most districts and even harder for a defendant to get a favorable judgment. Any teacher who ignores this fact does a disservice to the students.