Earlier quoted context omitted.
This is the thing when I see wall street, and specifically high frequency trading vilified. Income inequality, the plight of the middle class, etc has almost nothing to do with that kind of financial maneuvering. Getting rid of high speed trading won't affect the average person really at all - but yet it's constantly vilified.
You're probably correct here. The part people find a little unsavory is not that it's somehow eroding the middle class. It's the idea that HFT can act as an unnecessary intermediary, essentially taxing a transaction that otherwise didn't need to be disrupted and at scale the amount extracted becomes material. Imagine your neighbor owned a Ferrari and you told him one day you were going to buy a gallon of milk at the…
What your described is more like real front-running: A customer places an order, the evil broker sees it and goes out in front to buy for himself then gives the customer a lower price.
Your buddy in the Ferrari reliably making money requires him to be able to properly predict. AND you're missing the other side of the trade! The poor shopkeep that priced at 399 when you were OK paying 401. Why should he lose out?
HFT market makers solve this.