When Atticus leaves the courtroom in To Kill a Mockingbird, why did those people sitting in the balcony stand?

Those people sitting in the balcony during the trial scene
of the novel To Kill a Mockingbird--aside from Scout, Jem, and
their friend Dill--are black people, of course. In that bygone era of Jim
Crow legislation and widespread segregation across the South, it's not surprising to see
the blacks having to take the supposedly least desirable seats. (“Supposedly,” I’ve
written, because sometimes the balcony seats are actually the best. These seats give the
best view of the courtroom drama in the novel, for example, and center balcony seats are
often the best seats for musical performances in
general.)

The black people in Harper Lee's novel stand to
honor Atticus Finch, whom they view as their advocate because he served as the legal
defense for Tom Robinson.