Oh, so it really was possible for a Ugandan university student not to have heard of Karl Marx? That sounds like a fascinatingly different intellectual and social atmosphere than the ones I'm used to, I stand corrected! Of course he had good reason to play naïve with the FBI man since the feds were fishing for a reason to paint the Civil Rights movement as a Communist plot, but given how he maintains his ignorance at the time decades after the need for it was gone there's little basis to disbelieve him.
What awes me is that Mamdani was later made actually stateless when Milton Obote's government stripped them of citizenship for his dissent, but he went back AGAIN after Obote was disposed. Like there was nothing that could stop this Ugandan man from being Ugandan and he persisted despite two different regimes' attempts to get rid of him, you gotta love that xD