Earlier quoted context omitted.
I see where you are going here, but it seems to be many orders off magnitude off in time relative to HFT.
its highly counterintuitive to see the modern system in the same terms as the capital markets of last millennium. and I'm convinced the system isn't perfect, I'm sure there are things that should be changed. I'm merely suggesting that the market sped up as people learned to do market stuff faster, and that market stuff is ultimately a process of allocating capital resources.
Put it another way, if the number of HFT trades were suddenly cut in half, what 1st order impacts would be felt by people outside those markets? The heart of the "but we're providing liquidity" argument is that this is a service provided that has real value outside the market. If that's not true the particular argument falls apart, doesn't it?