But that price discovery should reveal the price that the underlying security is worth.

If shares were only traded based on what other people trade it for, isn't that the blind leading the blind, and the price it is traded for will have little grounding in reality.

I have several issues with HFT, however 'spoofing' as it is described sounds like it should be perfectly legal to me. If a player wants to trick the market, it is an irregularity that should be capitalised on by someone with a better understanding of the true value of the security