Huey's speech actually shows how progressive and Marxist the Panthers were. Although focused on the struggle of black Americans at the time, the Panthers realized that racism, and indeed all oppression, was a result of the capitalist system and NOT the actors IN the capitalist system who happened to be mostly white, male and straight. Oppressors can be any color, gender, or sexual orientation. They only have to support capitalism and they're supporting oppression. Anybody and any group who uses the Panthers as models of black nationalism or black separatism is barking up, not only the wrong tree, they're not even in the right forest.
This also ties in to the part where the narrator talked about Marxists only being concerned with economics and not social issues. What he didn't bring out is that, to the Marxist, the economics and the social, and also the political, are inextricably entwined under capitalism. You can't effectively separate them because capitalism needs them all to enforce it's system of oppression. So to fight on social issues alone is ultimately futile because you cannot liberate socially without liberating economically and politically too. Of course a Marxist WILL be concerned about the economics of the matter because social and political oppression actually flows out of the economics of profit and private property inherent in capitalism.