You're implicitly begging the question by assuming that HFT is bad, and therefore permitting it is bad, regardless of any further evidence. The point here is that if an exchange successfully removed HFT, and that materially hurt people, that is evidence that HFT isn't bad.

I'm simplifying a simplification, and I personally would be among the first to point out that this is still just a one-point sample of a horrifically multidimensional space. My point is not to specifically claim that HFT is good, a matter that I still have no personal opinion on, but to point out the question begging. If HFT is shown in fact to be a net gain for consumers, then you should not blithely carry on with the presupposition that it is bad.

I was replying to this:

*"...If that happened because HFT market markets decided not to use the TSX anymore and instead haunt exchanges that were amenable to HFT, that's evidence that HFT was helping individual investors..."

Which claims that because people move to places that are not regulated/taxed it's a proof that HFT was helping individual investors.

That was in return in the context of me asking whether the reason why the Canadian market lost out was because it did so alone.

In other words. If ALL markets included taxation would the same drop happen? Or in even other words. If something can't handle being taxed is that an argument for not taxing it? Wouldn't it just be evened out.

I am not assuming HFT is bad or good. I am actually trying to figure out what exactly it's good for.

I understand how it's good for those who trade on the market, what I have not yet seen is any examples of how that transcends to society as a whole. And until someone can give me obvious examples of that I don't believe it's irrational for me to be sceptic.