The perception comes from the undeniable fact that it was the white majority that establish, ran, benefitted from, and fought to protect a government backed system of racist policies for several hundred years. That historical fact can't be swept aside - it happened. And for that reason moreso than anything else, there will ALWAYS be that perception. Every so often news leaks out about a company with a glass ceiling that restricts blacks exclusively - this being perpetrated by whites. This adds fuel to the perception and strengthens the resolve of those who want to point out that racism still exists, its directed at black people by white people, and nothing is going to make it go away.