Yeah, it was sometime in the 90s when there was a meeting between music producers and the people who owned private prisons, hence why there's such a marked difference between pre-90s rap and post-90s rap. There isn't a whole lot of documentation on it because it wasn't exactly done openly, but there's been a few whistleblowers since then, and if one digs you can probably find evidence of it. I never saved the evidence, as if I were to try and compile documents on the crimes and seedy dealings that have gone on I'd need like 50 harddrives just to fit a tenth of it.
And yes, they are all part of the same (((tribe))).
Yes it is known fact that the record labels much rather promote rap musicians that peddle violence, drugs, sex with a hundred thousand hoes, the list goes on & on. If a musician wants to talk about something decent like Christianity, raising his kids or curbing the violence, they (((())))) in their shiny Manhattan NYC & Los Angeles offices typically won't promote it. I worked as an music intern for a little while during college many years ago & always wondered why we'd be forced to market a lot of junk while there was better stuff out there that should've been pushed. The powers that be know that the rougher material easily sells to today's degenerate audience & some of these producers make these songs awfully catchy for the typical teenager or 20 something listener that twerks in their car or in the boozy pill-laden nightclub.