I don't know enough about IEX to know whether the below is true. If IEX has this 'magic shoebox' mechanism in place, it might follow that they care about establ

I don't know enough about IEX to know whether the below is true. If IEX has this 'magic shoebox' mechanism in place, it might follow that they care about establishing a fair exchange in other ways too. There are hundreds of ways in which HFT firms profit from understanding the architecture of various exchanges. In some (many?) cases, HFT firms know more about the exchange architecture than the exchange does. The 'shoebox' addresses just one (mostly outdated) source of HFT competitive advantage. Perhaps employees of IEX drink the koolaid because the exchange actively seeks to eliminate architectural areas of unfairness. The only thing publicized is the 'magic shoebox', but perhaps there are many more such features. Again, this is just conjecture.