They are lumping China's monopoly money economy into the western's, and saying 'look, central banks are keeping the stocks afloat.'

No, that's not how this works. Western central banks put some money in, Western stocks rise and fall due to speculation, just like always. China used fake chinese money to 'buy' fake chinese stocks for pump and dump schemes, to lour in gadfly investors from the west. They paid the authors to lie, and now the honeypot awaits western money to feed the chinese debt trap.