[baobabKoodaa]

Shkreli didn't "return every penny to his investors". He stole money from one group to pay another group. Yes all of his investors ended up in the green eventually (because some underlying businesses were profitable), but that doesn't change the fact that he defrauded a lot of people and not "every penny" was paid back.

For example, if you invest money in a profitable business and the CEO skims a little bit off the top, you might end up making money despite that you were defrauded off some of your gains.