For your argument to make sense, all forms of corruption would need to have a single cause, and all interventions to reduce corruption would need to impact all forms of corruption. That's nonsensical and not a point I'm willing to engage further with.
I think we've pushed this thread far enough to the right margin of the page.
You implied that, without HFT companies, we'd be right back there, though I see now that you didn't explicitly say exactly that.