ichabod said:
Just because it is widely considered bad english doesn't mean it is. Truth is not the same thing as public opinion. As I said, dialects are rarely called such for scientific reasons. People speaking Chinese "dialects" often have a harder time understanding each other than some people speaking different northern European "languages."
What you are advocating is a proscriptive approach to language. But language is not something some guy invented. It grew and evolved, and continues to evolve. A proscriptive approach is like deciding that heavier objects fall faster, and then when they don't, calling it "bad physics." You can say that ebonics is not the same as standard english, but to say it is bad is to apply a subjective, pejorative term to an objective reality. It's like saying people who have red hair have bad hair because most people don't have red hair.
I think the problem here is that everybody is looking at it as a binary issue. They are either on the "Language should be standard" side of the fence or on the "Language evolves" side of the fence, neither of which really represents reality.
Language does evolve; we are not talking in 12th century English (or in Latin, for that matter - or the grunts of a caveman). However, that doesn't mean that there is no such thing as bad English.
The reality is that language does have standards, but that those standards are what changes or evolves. You can imagine the standards as two markers on a long line which represents the language as a whole. At any point in time, you can place two markers on that line and say that any language between those markers is OK, and any outside them is bad.
Of course, each of us will place the markers in different places. We'll all agree that a certain area of the line is definitely within the markers, but some will say that those markers are a little further apart than others. As time goes on, those markers both move together along the line - eventually what was indisputably right in the middle of the markers is on the edge of the space defined; and for some people, who place the markers a little closer together, it's now outside them.
So both are true. Yes, language evolves. But also yes, there is such a thing as bad English. There's a grey area - not two polar opposites of evolution and static standards.