Answer
"Black English is the creation of the black diaspora"
As indicated in the article referenced in the question, language evolves because people have a deep collective need to communicate the realities of their conditions in a way that makes meaning to them as well as to others. To be forced into a language system that disallows them from doing that, or dampens their ability for self-expression translates to the submergence of a people. Aristotle put it succinctly. He states that "freedom is obedience to self-formulated rules"
So if people are truly free, then they reserve every right to express themselves how they chose.
Another section of the article which speaks strongly to the subject matter states that the rules of the language are not self-determined by the nature of the language itself, but by the very things, experiences, emotions, desires etc that the language must communicate.
Cheers
