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.
Everything you bring up involve two parties transacting with the knowledge of the other party and both parties benefiting from the transaction. Once again, how does this compare to the HFT? Nobody's been able to answer this question, they just pull a red herring out or straw man and start harping on something I never said or insinuated.
I guess such is the nature when the opposition realizes that they are losing the argument... I imagine that the ad-hominems are not far off.