Except for the fact that people don’t know what the price is even with all available knowledge. HFTs serve a pretty useful function in converging to a discovered price the market can bear continuously. Prior to HFT markets were generally less stable on their pricing and liquidity was much worse. The fact you can basically trade at any time on anything instantly is made possible by HFT.

I look at them as providing a service like an energy exchange does in ensuring power distributes evenly and regularly across a region across providers and grids. They clip a fee in the middle but they provide a service in stable supply and prices.

This doesn’t mean automation isn’t without risk, and like an energy exchange, when things go badly they can go very badly. But by and large you never notice either the HFT or the energy exchange while you benefit from their existence.