You are correct in everything except your description of the dysfunctional culture as a “sub culture”.
The real problem is that violent and dysfunctional culture is the dominant culture in today's Black community, not some subculure limited a to a small segment of the community.
The segment of the Black community that is hard working, educated, productive and plays buy the rules is the Black subculture in the Black community.
They are the Oreos and are hated by the member of the dominant Black culture more than whitey is hated.
I live in north Texas. People intermarry here a lot. Caucasians, Koreans, Mexicans, Latinos, Cherokee, Creek, Sryians who left in the seventies, just all sorts of mixed race couples. With all manner of mixed race kids. Go to any Kohl’s or Target or Walmart. Or, for that matter, most churches here. That is what you see.
So, where I live the demarcation line is not as clear as what you are describing. Here, the black gangbangers frequently run with white or mixed meth heads - and the meth heads are every bit as unpredictable and dangerous as inner city ghetto dwellers.