Well, there are nuances here. HFT may not be a net win for humanity, but it's a long leap from there to "no arms race benefits humanity". The last large "arms

Well, there are nuances here. HFT may not be a net win for humanity, but it's a long leap from there to "no arms race benefits humanity". The last large "arms race" was a decades-long contest between the US and the USSR. It resulted in millions of deaths (via proxy wars and famine), the near-bankrupting of several contestants, and several cases where we almost turned our civilization into glowing dust. It also got us, as a species, to the Moon. It encouraged hundreds of thousands more people to study engineering and hard sciences, created the interstate highway system, modern communications, telemetry, trauma medicine, epidemiology, etc. I won't get into a discussion of whether all that was worth the cost, but it's no coincidence that technology advances quickly during times of war and near-war.