AskHistorians

The troglodytes that support racism are generally not good at economics.

They weren't equal facilities. Black schools were more of a one-room staffed with volunteers and paid for by donations kind of thing. It was really, "We made this society, and you have to stay out of it". Separate but equal was just propaganda.

They thought it was worth it because they were racists that didn't want to share facilities.

Also, usually the separate accommodations were much better for the white people, not as much was spent for the other side.