Trying to do everything outside of the system will result in failure.
Why? Why can't you have the robots battle each other and have the "moral" people trade on their own exchange?
Nobody here has given me any rational reason as to why HFT is a good or moral or productive or beneficial thing. Therefore it should be stopped.
This is the type of prevailing attitude I hate about bureaucrats. It's not that there is anything morally righteous about HFT, although I do agree that it does help with liquidity, although I see you're point with orders that are placed and cancelled, never to be actually traded upon. These are the same justifications that bureaucrats use to outlaw things like drugs, violent video games, and could be used for things like luxury cars, yachts, etc.