In To Kill a Mockingbird, what does Atticus find wrong, what right, with the idea that all men are created equal?
In Harper Lee's To Kill a Mockingbird, I believe that the idea of "all men are created equal" is something that Atticus struggles with.
Atticus feels that all people are equal morally and under the law, and that skin color and one's heritage should have no bearing upon the value of the individual.
However, Atticus struggles with his community's perceptions of equality. Atticus' morality will not accept how his peers treat those who are supposed to be "equal."
In Maycomb, the town in which they live, some people consider themselves more equal than others. The whites of wealth and property consider themselves superior to those whites of the lower classes, and don't consider blacks to be human beings at all.
Ironically, Bob Ewell believes, even though other whites consider him "white trash," that he is far superior to Tom Robinson and his "kind" because Ewell has white skin.
All the little man on the witness stand had that made him any better than his nearest neighbors was, that if scrubbed with lye soap in very hot water, his skin was white.
As Atticus tries to see the individual rather than, for example, skin color or social status, he is disappointed with those tied to the past (the Civil War) and societal expectations (upper vs. lower classes), and their use of these things to judge the value of others. Equality is not subjective, nor are there different kinds . Atticus would see the concept of equality open to all people.
Atticus subscribes wholeheartedly to Jefferson's famously inspiring words in the Declaration of Independence which declare that all men are created equal. Indeed he refers to it in his closing speech to the jury in the trial of Tom Robinson. But this notion of equality is a formal, legalistic one. It doesn't relate in any way to the substantive differences existing between us, the different talents, aptitudes and abilities that make us what we are. To that end, Atticus criticizes the attitude of many progressive educators who think that equality involves educating children of mixed ability in the same way.
Atticus knows that we're not all equal in some respects. Some people are more intelligent than others; more hardworking, richer, better at baking cakes, and so on. But all of nature's inequalities get left at the door of a courtroom, because inside a court of law, everyone is formally equal—rich and poor, intelligent and stupid, male and female, black and white. Courts are the great levellers of society; inside them all men are indeed created equal as the Declaration of Independence so clearly states.