Disclaimer: I work at an HFT shop.
A very basic question: if you wanted to buy 100 shares of MSFT right now, who takes the other side of the trade?
High Speed Trading does NOTHING for owners, investors, the company or anyone but the traders themselves.
This is a false statement. Owners, long term investors, etc. value the option of immediacy. That is why options have intrinsic value. If there were no market makers (speculators), it would be almost infeasible to enter or exit a stock position without considerable cost. HFT market makers actually decrease the transaction costs of long term investors by tightening the bid-ask spread (for hundreds of stocks, the spread is as tight as legally possible: 1 penny).
A common misconception is that high frequency trading is like operating a money printing machine. This is also false. High frequency traders take on risk every time they take the other side of your trade. On average, if they're intelligent, they'll be compensated for that risk. In the end though, there is no such thing as a risk free trade. Even pure arbitrages have risk inherent in executing all legs of the trade at once. Pure arbs are very hard to build a business off of in practice.
One other point I'd like to make is: what is the point of this ridiculous speed? If you're confident in your ability to adjust the prices you're willing to buy/sell at very quickly in order to react to new information, then you can make tighter markets. Making tighter markets (if you're intelligent and fast) is desirable for the market maker because it allows him to capture more order flow at what he believes is a fair price. Tighter markets also lower transaction fees for end users of the market. In reality, all this HFT cuts profits away from all market makers (per unit), especially compared to when markets were insanely wide back before electronic trading.
Greed has nothing to do with it, and as I pointed out before, "money for nothing" is the complete opposite of what's going on. High frequency traders take on risk in the expectation of some small payoff. The compensation (on average) is the natural result of risk transfer. I don't think high frequency traders are greedier than people in any other business. Are they profit motivated? Of course. But so is Wal-Mart, GE, and almost every person doing a startup. I think "greedy" is an unfair assessment.