It is because in America, the white people abhor people who are a different color or racial than them. They have inherited characteristics from their ancestors. But the reason why slavery became more common as slaves because they are immune to European diseases than indigenous slaves such as Indians of the West and North America. The African American were better labourers. The Indians are food gatherers, notate not skillful and crafty as African Americans with planting crops and nurturing animals. Not only the African American are skilled in growing crops in tropical conditions, they are also skilled at craftsmen such as iron workers, miners, and carpenters.
These pictures shows African american, white people, and the Indians These 3 race of people was the choice of slavery. But African American was the most common due to their skills, and the white people and Indian just commit suicide, etc during task.