That was a compliment. I myself am neo-Marxist. If you owned a convincing wig, I'd probably marry you.
Radicalism is actually rarely caused by persecution, poverty or suffering. If that were so, the entire planet would be radical. Radicalism is caused by relative priviledge, travelling, relative comfort (the gift of being granted the time to think and contempolate), being caught between two or more societies, cultures or classes, and being forced into a position to be able to compare and contrast.
King wasn't a poor black man, his family was fairly wealthy. Gandhi was well educated and priviledged, Guevara was part Irish and a doctor, Napoleon was Corsican, Marx himself lived in England and was related to bankers, Bob Marley was half white, Wilberforce (instrumental in ending slavery) was a rich dude, Ho Chi Minh (Vietnamense independence) lived in England, Toussaint (revolution in Haiti) was son of a King, William Wallace (Scottish independence - Braveheart!) was a rich dude, Darwin (father of evolutionary theory and an abolishionist) was a son of doctors etc etc. All were outsiders forced into seeing the world from a more objective vantage point. And look at the lives of radical writers - Orwell, Wells, Steinbeck etc. They're rarely from the lower classes, always relatively comfortable and always caught between worlds.
Another example: in 1968, France was shut down...
en.wikipedia.org/wiki/May_1968_events_in_France
...by university students and posh kids, people not tied to jobs or the working class. Only then did unions and workers jump on the bandwagon. And the “Arab Springs†were driven more by the under-employed well-educated than the poor.
He means there is no meaningful anti-capitalist "cause". That kind of radicalism died in the 1960s. It's probably more likely that some technological advancement or some minor bit of political legislation transforms capitalism that working-class rebellion.