It's a matter of taking the side of the weak against the strong, something the best people have always done.

Her novel Uncle Tom's Cabin (1852) was a depiction of life for African-Americans under slavery; it reached millions as a novel and play and became influential in the United States and United Kingdom. I will only say now that it was all very funny—and we were ready to explode with laughter all the while. It energized anti-slavery forces in the American North while provoking widespread anger in the South.