As a product of a HBCU I had to chime in. There are plenty of white folks at HBCU's, especially state schools, because the tuition is so cheap for a state school. When FAMU's lawschool was reopened, I knew that school wouldn't be all black because white folks want to take advanatage of that instate tuition and the location. You go to any HBCU you will see folks of all races there, people from different countries. I never saw "racism" against white folks, I think the white folks who go to HBCUs generally have a positive experience and learn alot. One of my good friends from highschool went to FAMU and got his Pharmacy Degree from there, he wouldn't change a thing.
As far as white members of NPHC organizations, well I haven't seen that at too many HBCUs in the dirty south. That's another thread though..