“Ebonics” is not simply people ignoring standard English rules of speech. It actually has its own set of rules which are adhered to. As such, you can legitimately call it a dialect of English. I would find it interesting to spend a class or two learning more about the proper rules of grammar for this dialect, and how they evolved, if I were an English major taking a specialized class like Jersey Jeepster. However, I’d be hard-pressed to make space for it in a high school curriculum, where the students are less mature, the public scrutiny is likely to politicize it, and few but the most advanced students really understand the parts of speech in standard English. Actually, this would seem to make it a more useful topic of study here, as opposed to the dialects of English spoken in New Zealand or Sri Lanka.