Your described scenario with Accenture doesn't describe a market-making HFT strategy. You're describing something akin to a mean-reversion algorithm that would

Your described scenario with Accenture doesn't describe a market-making HFT strategy. You're describing something akin to a mean-reversion algorithm that would be MFT or slower, and is not a market-making strategy. It demands that you buy and hold inventory to profit. It doesn't provide liquidity. Of course you can make a huge profit when a crash occurs, whether that crash is due to a vicious circle of algorithms, or a vicious circle of human psychology. There are algorithms out there that look to do just that, trying to profit from exploitable market anomalies, and it's great that those people have found a way to get paid for fixing some problems. But they're not HFT market-makers, they're a different group of quant/algo traders. Personally I care little about HFT. The flaws in the technology will get ironed out; the competition for the low-hanging fruit will continue to intensify, and eventually many of the functions will become commoditized as they mature. In the meantime, I think it makes sense for HFT market participants to be sensitive to the fact that many individual market participants have trouble identifying the value they've received because of HFT participation, but can clearly remember fears that have been induced by HFT driven events.