My opinion, but I think one of the biggest contributors to all stocks sliding is less manipulation than the stupidity of removing the uptick rule on short selling. This was put in place to prevent exactly what we have experienced in the market. People could not short a falling stock because they had to short on an "uptick".

When the SEC eliminated the rule, it allowed traders to pile on to falling stocks and drive them down hard.

That, my friends is why I think the market has crashed so hard.