What does the male-macho ‘serious revolutionaries,’ mean?

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A few infrequent meetings were, eventually, arranged, but only after Cynthia sent Lennon stern words on his absence. Legend tells us father and son were bonding before Lennon’s death. Son says otherwise. “It was still very distant,” Julian said. “There were cuddles now and then but there was always an uneasy tension.” He would be in his 30s before he’d receive anything resembling a fair share of Lennon’s estate. Lennon said it wasn’t until he met Yoko that he saw the error of his chauvinistic ways. But they would go on to make some grave errors in judgement together. “The biggest mistake Yoko and I made in that period,” Lennon wrote in 1978, “was allowing ourselves to become influenced by the male-macho ‘serious revolutionaries,’ and their insane ideas about killing people to save them from capitalism and/or communism (depending on your point of view). We should have stuck to our own way of working for peace: bed-ins, billboards, etc.”