I really hate to go down this road because it's been rehashed thousands of times on Hacker News... And I've yet to see a convincing argument that HFT is of any

I really hate to go down this road because it's been rehashed thousands of times on Hacker News... And I've yet to see a convincing argument that HFT is of any benefit to anyone else other than themselves. At the most basic level, HFT firms make money, right? Otherwise they wouldn't be doing this. Where does this money come from? Entities that are holding these same stocks for longer periods of time. It increases the costs to the longer-term buyers, and it decreases profits to the long-term sellers. HFT is sand in the gears of the economy, not lubricating oil like they would have you believe.