Retirement savers are not churning their portfolios and are thus not paying anything to HFT. Not a strong argument.

Making money making markets takes risk capital. i.e. Money. The money makes more money. Fact. I agree. But don't blame HFT. Blame finance. That is how finance works. I see a completely legitimate case for being anti-finance. I don't see a legitimate case for being anti-HFT only. Indeed, the opposite, if HFT reduces the bid/offer paid by the average retail investor. Which it does. Fact.

Do you know who hates HFT even more than the general public? Human market makers. I think that says more than any of my arguments.