I work in HFT. We do not front run orders. We make money by finding correlated assets that when traded together, will create profits more often than not. Usually there is a mathematical relationship between the two (this is what the Black-Scholes model proved and won Nobel prize).

The reason that this trading style is called "High Frequency" is that everyone knows these relationships and therefore it's a race to get there first. Much like the scene from "Glengary Glen Ross", the first person who gets there gets a lot, the second person gets a nibble and the third person gets nothing.

The whole value of this is profits for the firm and high liquidity for everyone else. Not saying it's a noble pursuit, but we follow all the SEC, FINRA and other market regs (most importantly NBBO).