Occasion: The immediate occasion that made Blow write this seems to be Micheal Dunn case, as he writes of it in his very first sentence. In addition, the hundreds of years of prejudice and racism that the African-Americans have faced also increases the likelihood of him choosing this topic.
Audience: I believe that he is speaking more towards the white race; most likely the ones of higher authority. This is because he talks of the discrimination of blacks from police, teachers, and court judges. All of these people deal with the whole society, and through the collection of data, it shows they tend to discriminate blacks, and lean towards African-Americans as if they cause trouble.
Purpose: The purpose is to show how much Americans do discriminate African-Americans as trouble makers, and that they are receiving more punishments, and inequality then the normal White American would. He wishes to demonstrate how society has brought African-Americans to see themselves as the low-end of society, and therefore, often do serve up to the discrimination. This is obviously personal to Blow, because he is African-American, and has experienced this discrimination first-hand.
Subject: The topic of this story is the discrimination of African-Americans in the American society.
Tone: Charles Blow uses a indignant tone to show that he is angry towards the injustice of discrimination. He uses this tone to emphasize to the audience his obvious distaste for the discrimination.
The overall purpose of Charles Blow's article is to speak out against the prejudice that is forced on the African Americans in this society. Throughout the article, Blow includes multiple statistics that show the true act of discrimination. He describes the fact that when police pull over Blacks, they are three times more likely to search the car, and that juveniles that are arrested are more likely to have longer sentences, more likely to be charged with the crime, and more likely to be tried as an adult when the juvenile is Black. He uses this all to support his point of the harsh realities of discrimination that is forced onto African Americans. Blow then goes on to argue that this discrimination is often times shaped into Black individual. He explains that a young African American often sees the way society sees him, and in turn he is shaped into that individual. Through this argument he supports a radical argument for even more change against the Black discrimination. This point is needed to reshape and challenge Americans to treat everyone with the American spirit of life, liberty, and freedom. It is needed to challenge us to impose the true definition of equality in a society that says they heavily support it.