Says who? Insider trading is illegal, so are you saying it doesn't happen? I think your belief that the system works like it is defined in someones definition ignorant.
Just like to add Google HFT Firms Front Running and let me know if that is enough info to convince you.
The first result is an article explaining how HFT can't front run [1].
How about instead of making vague arguments about how HFT does front running, provide a specific example of how HFT actually does front running as you claim.
And no, one anecdote is not enough. You have to prove that there is a systemic fault in the way the HFT trades in the market that allow them to operate illegally at scale without any repercussions. To find one HFT firm guilty of front running and then claim that they all do would be tantamount to saying all hedge fund managers cook their books just because Bernie Madoff did. I'm sure you can see the absurdity of that accusation.
Front running requires that you trade in front of your customers. So end customer calls up his broker, asks for 5000 of XYZ. The broker then quickly goes and buys ahead of him, to get in on the action.
HFT firms don't have customers generally. So they can't front-run even if they wanted to. They'd have to make a deal with someone that does have customers. That's a pretty big conspiracy theory. And it isn't needed because HFT can make money just by seeing what orders hit the exchanges; no need to know about the orders before that.
Just like to add Google HFT Firms Front Running and let me know if that is enough info to convince you.