According to the Washington Post, "the reasons for black kids to be homeschooled may not be the same as for white kids. (Ama Mazama's research) shows that black parents homeschool their children due to white racism."
Covert Institutionalized racism
Eurocentric teachers' attitudes
Racial stereotypes of black children
Harsh school punishments
As a former public school parent who is black and has black children, I can attest to many of these problems. We certainly experienced them. The worst for us was the racial stereotypes of my family in general. When we moved to GA, for example, there weren't many black families in our kids school, and it was abundantly clear that the staff had ideas about black people and just assumed that those things were true about us. I had people purchase my kids' field trip shirts because they assumed we could not. ( I'm pretty sure we made more than those folks.) I had teachers thank my husband for having lunch with his kids and ask him when was the last time he saw them (as if we were divorced). I had teachers tell me how they "understood" how hard it was to be a single parent. Since I was married, I had no idea why they would say that to me.
In short, I felt that they had low expectations about us as people, and so also had low expectations for our kids. So while we may have not realized it at the time, racism may have had something to do with while we pulled the kids out of school.