These are students. I would not expect them to start their education knowing about whiteboard interviews. At some point, all of us professional software developers were ignorant about how interviewing worked, and then we learned.

The question is: why are black and hispanic students not reaching this level of understanding at the same rate as whites and Asians? Perhaps they're not doing internships at the same rate? Some other reason? Regardless, this question deserves a serious answer, and not a flip dismissal based on stereotypes about work habits.