While nobody would argue that there are no racists at Ole Miss, they are not anywhere close to being a majority of the students. The elected Associated Student Body President at Ole Miss is a black woman. The elected Homecoming Queen this year was black. Heck, even Miss University, the university's delegate to the Miss Mississippi Pageant (and possibly Miss America) is black.
There is no "racist culture" at Ole Miss, but like everywhere else, there are racists. It's just unfortunate that the whole student body gets tarred with the same brush as the handful of drunk frat boys who were responsible for this incident.