i'm not really talking about white people at all, because obviously there are some who would be and wouldn't be shocked at widespread racism by white people.
this is a subtle point that you are missing, which is ironic because you are 25% asian, i imagine you have seen quite a bit of anti-asian racism (it's just a joke bro! don't you love being the butt of jokes? who doesn't love that!) from white people because they have no idea you have asian family.
and i'll just pre-empt your next point: i'm not saying only white poeple can be racist, that's obviously not the case if you've ever been overseas, and anti-white racism also happens a lot in america.
i'll generalize my point for you, so that you may understand:
no person of a minority race would be shocked that the majority race harbors a not-insignificant subpopulation with vehement racist views against other races. if every single majority race were to spend a week as a minority, that would likely dispel any notions they had of the contrary.
^ this works for all races.