No they don't. China has bought bonds equal to 9% of our debt. China cannot demand payment until maturity date on those. Many of those bonds also have interest rates lower than the rate of inflation, meaning in essense the Chinese are paying us to purchase those bonds. Factes matter.
Since all money is created from debt and China owns our debt, they own our money. Anyone who buys bonds, owns our debt, our money. That's why bond sales have a direct impact on the strength of a currency.
The imbalence you note is driving people away from subsidizing our debt. This is why the Federal Reserve has to directly purchase it now with what they call quantitative easing. The danger in this is that the Fed doesn't have real assets to back up the bond sales, not like China. The Fed is simply creating the money to buy the bonds.
The end result of this...well, let's just say it's musical chairs and most of the chairs have been removed. Keep playing the music and pretend nothing is happening!