The dialogue furthers this. Much of which, I suspect, was written by Singleton, whom, it was reported repeatedly during production, didn't like the work done by Price and, so, rewrote it, with help from the ever-talented Jackson, who makes Shaft to the letter. Jackson is Shaft. Shaft is Jackson. Which should make for a great movie.
Shaft is, in a way, an urban hurricane.
Then makes Shaft, a cop, mad. And when he is mad he gets angry, wanting justice divine. But getting that information is almost impossible. Two years pass, the rich brat returns to the United States, Shaft, in wait, gets him, and marches to justice. All of which should make for a great summer movie.