I’ve written a few posts defending HF traders. Mainly ’cause I get irked by know-nothings haranguing successful traders . Tip to the know nothings, go and find something you can do successfully instead of bitching about those beating you. Even better, keep on doing what you are doing, more money for the rest of us (& BTW, thanks).
Here is a good article, Computers vs. the News: What’s Behind the Stock Market Chop?
Money quote about why the market is volatile:
This volatility reflects one thing and one thing only — markets react to news, and since 2007, there has been an abundance of news which has caused investors to panic.
Those blaming HFT for the volatility are idiots. Head-in-the-sand idiots. Do a bit of research, start by Googling (in no particular order):
US housing bubble
Read a book, Bailout Nation is a great start.
There’s more, let me know and I can refer you to other sources.