Headline from 1950: “Overturning Plessy vs. Ferguson would be a big mistake.”
You are thinking that Brown v. Board of Education voided Plessy, but it did not.
It created an EXCEPTION to the general rule of segregation in the case of public schools, based on "recent psychological research" which allegedly showed that applying the perfectly valid and Constitutional rule of "separate but equal" was not permissible IN PUBLIC SCHOOLS because the "research" showed that the "mark of inferiority" associated with separate schools was the cause of poor performance by black students.