A particular complexity of the character of Atticus Finch is his intolerance. Atticus demonstrates a number of virtues in the text, which makes this one element of his character especially complex and even surprising, though not inconsistent with the values that define him.
These values and Atticus' dedication to upholding them are seen in his behavior during the events surrounding the trial.
Atticus's own actions in arguing the Robinson case demonstrate this kind of courage, and his behavior throughout embodies values of dignity, integrity, determination...
Given these traits, we may be surprised to realize that Atticus Finch is unbending in his views and his condemnation of certain people. He calls these people "trash" and refers to them on multiple occasions.
Atticus defines his characterization of these people according to behevior based on poor moral judgement.
Unlike Alexandra, who calls poor people like the Cunninghams "trash" because of their social station, Atticus tells his children that any white man who takes advantage of a black man's ignorance is "trash."
Though it is tempting to view Atticus as a thoroughly loving and patient person, he is decidedly impatient with certain behavior. He makes this clear in his discussions with Jem and Scout when they bother Boo Radley and makes it clear again as he warns his children about people who are "trash".
The intolerance displayed by Atticus Finch is consistent with his character, while it does offer complexity, as it grows from the values he lives by.
At the end, Atticus Finch and the Sherrif, Heck Tate, both decide that they would say that Bob Ewell fell on his own knife. This was even though Atticus is a man that always believed in telling nothing but the truth. About why he told the truth, it was because he thought that it was a sin to kill a mockingbird, who was Tom Robinson as he got killed even though he did nothing wrong. (Bob Ewell was the one that attacked Mayella Ewell but, taking advantage of the fact that he is white and that, due to racial prejudice, he was superior to the blacks, told Mayella to say that Bob Ewell injured her, although it was Mayella (who was without friends) that was trying to be sexual with Tom Robindon and was caught by Bob, and she got beated badly by him (perhaps because he was the town drunk).
This is my interpretation of how Atticus Finch showed depth and complexity despite him being impeccable. Hope it helped. :D
Oh hi Beatrice.
I think I know you.