Your counterargument proves too much; if "people" don't have agency then you can't blame anyone for anything, including being unable to blame the Mongols for an

Your counterargument proves too much; if "people" don't have agency then you can't blame anyone for anything, including being unable to blame the Mongols for anything about modern China. The concept of blame becomes entirely pointless. This may, in fact, be true. But in this specific context, it's an argument that proves too much.