The key difference between ancient demo and modern demo

is what?

Ancient democracy is not completely protected by bullet-proof legal system like that in the US today. Ancient democracy can be side-stepped or interfered with whoever is in power, be it king, emperor or tribe leaders.

But modern democracy is protected by legal system. The state doesn't have absolute power over the legal system. Nixon can go down for his mistakes.

What is China's democracy? Basically it doesn't have one although it claims to have a "people's democracy". China's democracy is simply a beautiful name that fools people, but the country is truly run by State power. Its absolute state-power determines the policy, the housing market, the stock market and everything. If it wants to nail somebody, it can instantly put somebody into Jail or even executed.