Why does King choose to begin his letter with this paragraph?

In my opinion, the first paragraph has everything to do with the tone that King wants to set in his letter. Acknowledging his audience, Dr. King begins the letter with a marked lack of emotion and a pronounced focus on legalistic logic. In Gospel of Freedom, a book-length study of the “Letter,” professor Jonathan Rieder describes the first half of the “Letter” as the “Diplomat” portion, suggesting that Dr. King was deliberately controlling his tone so as to achieve his desired ends of changing hearts and minds. The phrase “diplomat” is useful because it reminds us that this letter is not a personal expression of inner demons, but rather a deliberately constructed epistle designed for a purpose. That it so successfully manages its tone is all the more impressive when we recall that Dr. King indeed began writing it while locked in solitary confinement, on scraps of paper smuggled to him.