The broker isn't selling your trading information. He is selling the opportunity to trade with you, and quantitative traders will pay him for that, because you are -- in all likelihood -- really bad at trading stocks. The professionals are so convinced that you have no idea what you're doing that they're happy to give you better-than-market prices, because the market is going to move against you anyway. (And of course, on average they are correct.)
You could make an argument of the form "HFTs have made trading so cheap that people are hurting themselves more than they used to, and we need to bring the price of trading back up so that people won't be tempted". But that is a pretty different argument than "HFTs don't provide any value". They clearly do. When you place an order to buy or sell stock, you pay lower fees and you get better prices than you otherwise would, because you look just like a million idiots.
You could make an argument of the form "HFTs have made trading so cheap that people are hurting themselves more than they used to, and we need to bring the price of trading back up so that people won't be tempted". But that is a pretty different argument than "HFTs don't provide any value". They clearly do. When you place an order to buy or sell stock, you pay lower fees and you get better prices than you otherwise would, because you look just like a million idiots.