The correct answer to this open question is the following.
The criticisms that King leveled at American society were that the American society was passive against the many injustices committed against African Americans and other minorities. We are referring to the document called "Letter From the Birmingham Jail," written by civil rights activist Dr. Martin Luther King Jr. on April 16, 1963, while King was arrested in jail. In the letter, King defended and explain his non-violent approach as a way to protest.