This bit from The New Jim Crow addresses both Bacon's Rebellion and why they made an economic decision to import Africans.
"Initially, blacks brought to this country were not all enslaved; many were treated as indentured servants. As plantation farming expanded, particularly tobacco and cotton farming, demand increased greatly for both labor and land...
The growing demand for labor on plantations was met through slavery. American Indians were considered unsuitable as slaves, largely because native tribes were clearly in a position to fight back. The fear of raids by Indian tribes led plantation owners to grasp for an alternative source of free labor. European immigrants were also deemed poor candidates for slavery, not because of their race, but rather because they were in short supply and enslavement would, quite naturally, interfere with voluntary immigration to the new colonies. Plantation owners thus viewed Africans, who were relatively powerless, as the ideal slaves. The systematic enslavement of Africans, and the rearing of their children under bondage, emerged with all deliberate speed—quickened by events such as Bacon’s Rebellion.
In an effort to protect their superior status and economic position, the planters shifted their strategy for maintaining dominance. They abandoned their heavy reliance on indentured servants in favor of the importation of more black slaves. Instead of importing English-speaking slaves from the West Indies, who were more likely to be familiar with European language and culture, many more slaves were shipped directly from Africa. These slaves would be far easier to control and far less likely to form alliances with poor whites.
Fearful that such measures might not be sufficient to protect their interests, the planter class took an additional precautionary step, a step that would later come to be known as a “racial bribe.” Deliberately and strategically, the planter class extended special privileges to poor whites in an effort to drive a wedge between them and black slaves."
It was also an economic and power dynamic decision to divide the public racially.