HIGHGATE CEMETERY, LONDON—On a summer visit to the grave of Karl Marx, Ben Gliniecki found that he would have to pay £4, or about $6, to pay respects to the man who sounded the death knell for private property. Mr. Gliniecki, a Marxist, said no. “Personally, I think it is disgusting,” the 24-year-old political activist said. “There are no depths of irony, or bad taste, to which capitalists won’t sink if they think they can make money out of it.” The charity that looks after this cemetery has long taken swipe at a different irony: Karl Marx’s decision to buy...