Actually, there have been a few threads with good sources that government does support the markets quite heavily. The government has admitted several times that they do perform market operations to support the American investor. I think in the 1990s during the Thailand, Latin America and Russian crises, the Fed has stepped into the equity markets as well as in the money supply with rates.
PPT does exist. The Nikkei has government support, like the national banks still holding equities bought from the top and not selling in order not to attribute the losses. Almost every government involves itself in support of their equity markets. It's good sense.
FOREX markets are manipulated every day by every major country in their individual favor.
It's just naive to think that everything is so nice and dandy in the US equity markets. There is already so much damn manipulation with specialists, MMs, hedge funds, I-Banks so why would not the government be involved.
BTW, those crazy rips like the one on Wednesday are quite unnatural. I'm sure the Fed starts them off and the MA technical signal is perfect since so many traders, big and small, will support it as well.