Because they are not keeping your money/stocks/tokens/whatever like they promised and should. Like all real brokers do. A bank run can not happen for a broker.
It is like Vanguard sending your money to their hypothetical Chinese subsidiary because that is where they think the market is most efficient. Then when the Chinese government seizes that company's accounts, you are shit out of luck because your money is not where it is supposed to be, and the US entity is bankrupt.
It is like Vanguard sending your money to their hypothetical Chinese subsidiary because that is where they think the market is most efficient. Then when the Chinese government seizes that company's accounts, you are shit out of luck because your money is not where it is supposed to be, and the US entity is bankrupt.