Earlier quoted context omitted.
This tired old contention that some great historical thinker is somehow single-handedly responsible for the fall of civilisation is nothing more than railing against intellect itself.
It is precisely the opposite. A world where Karl Marx isn't responsible for millions of deaths is a world where the existence of intellectuals is ultimately pointless. There, a wise potentate could send philosophers into labor camps and he'd only benefit from the elimination of waste. If you believe that ideas matter, then you should allow for spectacularly bad ideas to have spectacularly bad real world consequences.
to me this seems to imply ideas don't matter, or we wouldn't be living in a market-oriented society. I suppose there's still room for global warming to demonstrate your point.