Ah I know who that guy is. He hosted the series of shows on PBS where he took dna samples of people like Oprah, Chris Rock etc. And traced them to as specific a location as possible in africa. Many of the people were surprised that they had european heritages too going way back. He seemed in the tv series like a fairly calm dude.
http://www.theroot.com/views/skip-gates-speaks
He talks about the incident there in some more detail evidently.