In this case, that "...it is difficult to do harm because by preventing a concentration of power, capitalism prevents people from committing sustained, serious

In this case, that "...it is difficult to do harm because by preventing a concentration of power, capitalism prevents people from committing sustained, serious harm." Specifically, that capitalism is effective in preventing the concentration of power. From a perspective shaped by a strong commitment to an ideology and also by the Soviet Union being, in 1977, still a going concern, I can see how someone could err in this way. But that's no reason why we still need to take it seriously, four decades on.