What you write applies to regular investors, funds, investment banks, portfolio managers, etc. Speculators in general.
But you should really read up on what HFT is. I recommend the book Flash Boys by Michael Lewis. HFT traders do not "trade" in the market in the usual sense. They don't optimize markets, they don't bet on anything, they don't take any risk. Every other investor takes risks (calculated), and that's their contribution to the market. They hedge risks and discover prices for those underlying assets you are talking about. HFTs are exploiting the markets, take no risks and siphon the money out of those investors that actually provide a service for the market.
But you should really read up on what HFT is. I recommend the book Flash Boys by Michael Lewis. HFT traders do not "trade" in the market in the usual sense. They don't optimize markets, they don't bet on anything, they don't take any risk. Every other investor takes risks (calculated), and that's their contribution to the market. They hedge risks and discover prices for those underlying assets you are talking about. HFTs are exploiting the markets, take no risks and siphon the money out of those investors that actually provide a service for the market.