Hi filmackay, re "The only advantage they have over you is -...

Hi filmackay, re "The only advantage they have over you is - processing capacity to respond faster." I am not sure that is true. Their charges for trading are also much lower than mine.

The two artifical advantages of time and cost allow them great and unfair advantages.

re "HFT targets vulnerable investors, not vulnerable stocks. HFT will move to one stock to the other without concern, but they will only ever target vulnerable investors' orders" I also believe this is not true. Just as shorters target vunerable stocks via a debt convenant HFT do also. They may do it technically but that is what they do and the effect they have.

All traders be they human or computer are going to use the stockmarket to gamble but allowing circumstances that foster and reward that is, in the long run, destructive of the market. One of the reasons for the emergence of 'dark pools' was to negate having to deal with the added volatility caused and used by HFT.