Atticus Finch, in To Kill a Mockingbird by Harper Lee, is one of the most noble and reasoned characters in American literature, and how he treats people is one of the primary reasons for that. How he thinks about race and friendship is a good indicator of why he is such a beloved literary character.

The same thing that makes Atticus a good lawyer and a good father is what makes him a good friend. He gives Scout this advice about how to deal with people:

"First of all," he said, "if you can learn a simple trick, Scout, you'll get along a lot better with all kinds of folks. You never really understand a person until you consider things from his point of view…until you climb into his skin and walk around in it."

Atticus practices this philosophy in his dealings with young Walter Cunningham as he sits at the table and drowns his food in syrup, with Mayella Ewell who lives a sad life and is stuck with an abusive father, and with Mrs. Henry Lafayette Dubose who is cantankerous because she was battling a morphine addiction. Atticus respects them all.

When the children play their Boo Radley games, Atticus is not amused by their making fun of Boo; when Bob Ewell spits in his face, Atticus understands that Ewell is just trying to save the little dignity he was left with after the trial. Atticus follows his own advice and does not judge people.

Certainly Atticus is well aware of racism; however, because of his philosophy about people and his innate sense of justice, he is compelled to do what he can to improve things. He and his brother grew up with Calpurnia, and now she is an integral part of his home, someone he trusts to raise his children. 

The most significant demonstration of Atticus's view of racism is found in his representation of Tom Robinson in his trial. Of course Tom is innocent, but Tom is a black man who has been accused of raping a white woman. In this time and place, that was a certain death sentence for Tom. The fact that Atticus intended to actually defend him (rather than just go through the motions) almost gets him (and his children) killed, as well.

Jem and Scout take some grief about their father's actions and beliefs, and Scout finally asks Atticus if he is what people are saying he is: a "nigger-lover."

"Scout," said Atticus, "nigger-lover is just one of those terms that don't mean anything—like snot-nose. It's hard to explain—ignorant, trashy people use it when they think somebody's favoring Negroes over and above themselves. It's slipped into usage with some people like ourselves, when they want a common, ugly term to label somebody."

"You aren't really a nigger-lover, then, are you?"

"I certainly am. I do my best to love everybody... I'm hard put, sometimes—baby, it's never an insult to be called what somebody thinks is a bad name. It just shows you how poor that person is, it doesn't hurt you." 

From this we can infer that Atticus sees people as individuals and not as people of a certain race or class.

The greatest evidence of Atticus's commitment to live a life which respects people regardless of their color is what happens at the end of the trial. Tom Robinson has been convicted, but Atticus gave him the best chance at acquittal that anyone could have given him. As Atticus leaves the courtroom, the Negroes in the balcony stand as a sign of thanks and respect. 

Atticus teaches his children valuable lessons about how to treat people, and he lives exactly and consistently what he teaches. That is a rare thing.