The supreme court meant that the whites and blacks would be 'separate but equal' meaning basically that they would have the same thing but they would be separated. the reason it was faulty was because they never showed the quality of the items or privileges that were given. the blacks could have some moldy disgusting putrid bathroom while the whites live in glamorous tiled clean bathrooms- but they would claim it's equal because they both have a bathroom.
The "separate but equal" doctrine was ruled by the court case Plessy v. Ferguson. This doctrine meant that schools could be racially segregated as long as the educational opportunities remained "separate but equal". Many people thought the idea was faulty because African Americans were still discriminated against, and they continued to receive unequal treatment.