The monicker "oreo" is used mainly in certain parts of the United States as a derogatory term for black people who, as some see it, behave and live in a very typical "white" fashion. (The metaphor alludes to the expression "black on the outside, white on the inside", like Oreo cookies.)
I'm not exactly sure of this, but it's my understanding that the term probably started mainly as a racist term used by some white people against black people who were atypical of "black culture" (ie. were rich, highly educated, lived in rich neighborhoods among rich white people, etc.) and was later "appropriated" if you will by black people. In this case, however, the appropriation didn't change it to a positive term (like happened with the word "nigger"), but retained its negative connotation.
In other words, the term "oreo" is used by many black people in the United States as a derogatory term for other black people who they see as acting like white people. These are, as said, black people who do not act in a "gansgta thug" way, do not participate in that kind of culture, are often well educated, sometimes rich, may live in the better parts of the city, and so on. In other words, they live the life of an archetypal middle-class (or sometimes rich) white person. The black people who deride them often see them as "traitors" to the "black culture", and having become submissive to the oppressors and assimilated into their culture, or whatever.
So yes, there are many black people in the United States who resent other black people who live, what can be considered, a "normal" life instead of living in the ghetto (usually below the poverty line, and often with poor education) and being part of the black "gangsta" culture.
This is a quite well known fact, and it gets talked about to some extent. However, it's a difficult subject for progressive social justice advocates (or should I say "warriors"). The practice is definitely detrimental because it perpetuates a self-destructive lifestyle that keeps a big part of the population living in poor conditions, with low education, low income, poor living conditions, and with little to no prospect to make a better life. It also perpetuates and reinforces a very divisive and hostile "us vs. them" separationist mentality and is too often ridden with outright racism, with strong prejudice and even discrimination against a group of people based on their skin color (ie. white people in this case).
But the problem from the perspective of a social justice warrior is that these are not the "enemy" (ie. white males). They are the people they are trying to "protect" and fight for. Thus they find themselves in a very difficult and awkward situation where they recognize a pattern of behavior that's highly detrimental, yet they can't speak out against it very loudly, because they are uncomfortable criticizing and attacking the very people they are supposedly trying to "protect". Therefore even if a few such people do comment critically about the phenomenon, it's not a very hotly debated topic, and it's mostly ignored.
This isn't something exclusive to the United States either. From other western countries Sweden has become another bastion of this very mentality. More and more immigrants (even those who aren't exactly "black") are appropriating this same "black gangsta thug" culture, and the exact same kind of derisive attitude towards other immigrants who they see as "betrayers" of their "culture" (ie. those immigrants who have simply integrated into Swedish society and are living a completely normal productive life, like any other Swede).
Of course Sweden being what it is, this is a very taboo subject there. You can only hear it from immigrants who have become the target of such derogatory attitudes, and who dare to speak out.
Needless to say, the Swedish immigrant population is destroying itself from the inside by this kind of separationist attitude. And the Swedish government and media aren't exactly helping.