It causes segregation based on race; Black people speak this language, white people speak this one. We're trying to bring these groups together, diving their language won't help at all.
The difference that I see is that I was expected to learn and speak standard English in a professional environment while the perception among my peers seems to be that those who natively speak AAVE expect their dialect to be accepted in all settings.
Note that I was careful to say that this is my perception of the expectations of others. My experience shows that native AAVE speakers adapt their language in professional circumstances in exactly the same way I adapt my own.
Post hoc ergo propter hoc. Why isn't it a result of segregation?
In any case, talking about whether or not it helps seems to be pointless. The dialect exists whether it's helpful or not. If it's an obstacle to bringing people together, then we need to figure out ways to overcome that obstacle, not wish it away.
If we have to choose a causal direction, I'm pretty sure it goes the other way. Otherwise we'd say things like "The government are trying to take my job away." (what British English speakers would say) to suggest someone is stupid, but no one does. That sentence, from my American-English perspective, sounds just as "different" as "The government be trying to take my job away.", which is grammatical in Black English.