A better comparison would be: You find an online blackjack service that uses pRNGs, and can reverse the state of their decks in real time. Do you (a) notify the company or (b) play a bunch of blackjack and clean out the house?

George Soros didn't hack anything or steal anything; he made use of publicly accessible information to make a gamble and he won big. The consequences of that win were certainly crummy for a whole bunch of people and it's terrible that a lot of innocent people were put in that position, but to compare Soros to a criminal is pretty disingenuous.