To the excellent answer above I would only add that it is quite common for a place that is immortalized in fiction to begin to identify even more with that fiction. Obviously the town does not want to be recognized for bigotry, but it does want to associate itself with a much-loved classic.
Monroeville, Alabama, is much like the town of Maycomb. In fact, each year in the old courthouse the scene of the Tom Robinson trial is re-enacted. At the time of Harper Lee's publication of her novel, Monroeville was, like Maycomb, an agricultural community located just outside the plantation community known as the Black Belt. In the southern part of a state known as "the Heart of Dixie," the Jim Crow Laws were certainly firmly grounded in Monroeville. Indeed, many an inhabitant of Monroeville was not pleased by the publication of Lee's liberal text in 1960.