*all* the leavers have racist opinions ?
Pretty much every human on the planet has racist opinions of some kind or another.
The thing is we overlook racist opinions we agree with on the basis of 'facts' and 'statistics'.
Like that today. Like that in the 1930s. Like that during the crusades. Like that in the iron age. Probably like that in the stone age too. People overlook their own racist bigotry because they see it as factually and statistically valid.
The question is what actions they take based on them? Most regular people aren't involved in hiring or selecting who goes to which school. Racism is more dangerous when educated people and people with power engage in it. And so many people with BAs (and in the UK, PPEs) are treated as if they are educated in knowledge.
Education in promulgating establishment and counter establishment dogma and myth is not education in knowledge.
I'm using the international English definition of race, not the Merriam-Webster definition of skin color. Taking skin color as race has been widely and totally discredited by science, since skin color varies randomly too much.