You seem to be forming a habit of ascribing things to me I didn't say. It's getting a little embarrassing/annoying.
The Flash Crash was caused by the NYSE's faulty time-stamping system. It essentially broadcast false information that caused traders to think there was an arbitrage opportunity. This was entirely the NYSE's fault. See here for details: http://www.nanex.net/20100506/FlashCrashAnalysis_Part3-1.htm...
> And massive profits for companies that create nothing
They prevent you from paying even more to corrupt exchange specialists. This creates billions of dollars a year in value. They also have a neat ability to help the market recover from irrational crashes in 20 minutes, instead of lingering there for days or months while everyone is too scared to provide liquidity.
> and actually were the cause of the recent financial meltdown.
HFT is completely unrelated to the financial meltdown. The financial meltdown was caused by a housing bubble. HFT market makers don't even trade mortgage-backed securities. Those were traded over-the-counter (basically via phone calls) by investment banks.
If you don't know what these words mean, then look them up instead of complaining about it. If you want to make a point, it is your obligation to understand the subject matter. Don't argue about things you don't understand.