Why was Atticus moved by the black community's gestures in Chapter 22?

After the verdict, the African-American community of Maycomb wanted to show its appreciation for what Atticus had done for Tom Robinson and for them. Although he did not get Tom Robinson acquitted, Atticus treated Tom with respect and did his best when everyone else treated Tom like a second-class citizen.

After the trial, Atticus is surprised to be served chicken for breakfast. Calpurnia explains it is a gift, and Atticus is very grateful for it....

After the verdict, the African-American community of Maycomb wanted to show its appreciation for what Atticus had done for Tom Robinson and for them. Although he did not get Tom Robinson acquitted, Atticus treated Tom with respect and did his best when everyone else treated Tom like a second-class citizen.

After the trial, Atticus is surprised to be served chicken for breakfast. Calpurnia explains it is a gift, and Atticus is very grateful for it. It’s not the only food gifted to them.

Calpurnia said, “Tom Robinson’s daddy sent you along this chicken this morning. I fixed it.”

“You tell him I’m proud to get it—bet they don’t have chicken for breakfast at the White House. What are these?”

“Rolls,” said Calpurnia. “Estelle down at the hotel sent ‘em” (Chapter 22).

When Atticus is puzzled, Calpurnia shows him the kitchen, which is overrun with food. Atticus is honored, grateful, and surprised by these gifts. Calpurnia worries the black community was overstepping. She doesn't want Atticus to be upset. He is moved, not upset.

Atticus’s eyes filled with tears. He did not speak for a moment. “Tell them I’m very grateful,” he said. “Tell them—tell them they must never do this again. Times are too hard. . . ” (Chapter 22)

Atticus knows the people who donated the food cannot afford to do so. They have very little, yet gave what they had to show their appreciation to Atticus. This is why his eyes well with tears. Atticus is overwhelmed by the gesture and by the sheer volume of food. It seems like every African American in town gave him something to honor him for what he did for Tom Robinson.