Many of our current conceptions about the nature of 'The Man' come down to us from the
Blaxploitation movies.
Many of these movies featured a sinister force that was ultimately responsible for distributing drugs to the ghetto. It was insinuated that if you saw beyond the local pimps and pushers, and if you peeled away the layers of Mafia and other bad guys, you would get to the real power broker that was pulling the strings and victimizing the city. It was vague, but 'the man' was certainly in league with the government and rich folk.
The hypothesis itself originated with black nationalist rhetoric, and entered the mainstream through movies. Now almost anyone can complain "The man is keeping me down."
Interestingly, a similar bizarre alliance of the 'gubmint', the Mafia, Cuban exiles, and local bad asses is thought by many to be responsible for the Kennedy assassination, and, as a recent series of articles in the San Jose Mercury-News showed, the CIA was indeed engaged in flooding the inner city with drugs. So at least someone way back knew what they were talking about!