> It seems like a big investment and a lot of hard work by a lot of people! It's too bad they were using it to defraud people.
A great deal of the financial industry uses a lot of money and brainpower to play zero or negative-sum games. The more egregious of those negative-sum games are eventually made illegal, and some of the people playing them get punished. But speaking as somebody who used to write software for financial traders, it's a relatively short trip from "zero-sum game that is currently legal" through "negative-sum game that could well be legal" to "negative-sum game where we think we won't get caught".
It's true that one can societally justify a fair bit of that effort by pointing at things like more liquid markets, reduced trading costs, more accurate pricing, and the like. But approximately nobody trading for a living gets into the business because they care about any of those things enough to devote their lives to them. They're there to make money, and things like marketplace sanctions, regulatory investigations, and criminal enforcement are just another part of the cost-benefit analysis.
When I was in the industry floor trading was still the focus. One slow day at the Chicago Board of Trade there was a guy in a polar bear suit walking around the trading pits. One trader turns to another, says, "I'll give you $100 if you punch the polar bear." The second one shrugs, takes the money, walks over, and punches the bear. Turns out the person in the mascot suit was wearing glasses, so they end up with a cut on their face and blood trickling down. It also turns out that the bear was there to raise money for the zoo, and some CBOT bigwig was on the board of the zoo. If I recall rightly, the punching trader was banned for life. The colleague who told me this story just smiled and, referring to the $100 gained, said, "Bad trade."
I'm sure that there are plenty of people in the industry who look at these 10 guys and don't say, "What an outrage against the investors," or "I'm shocked that they'd tarnish the name of our industry that requires public confidence to function", but instead just smile and say, "Bad trade."