This song was a reaction to J Dilla being repeatedly harassed by the police.
In an interview with Ma Dukes, J Dilla’s mother, she told the story of Fuck The Police.
The police department was down the street from where we lived, and every time he pulled off they’d stop him and harass him. They even tossed the car once looking for something. Because he was young and clean-cut, they thought he was selling drugs. Proof was at the house one evening when James had another run-in with them. He had only gone to the gas station which was three doors away. I told him not to get upset because he was hurt to tears. He was so angry and just tired of being harassed, so I told him, ‘Look, this is what you do: you go downstairs and make a song about it, and you laugh in their face.’ And that’s when he came up with the “F” the Police’ thing.
Curtis Mayfield never sang / recorded a song called “Diamond in the Back.” The song that emp503 is referring to is William Devaughn’s “Be Thankful For What You Got,” which is often incorrectly attributed to Curtis Mayfield.