Well by gaming the lottery, they are taking a little bit of money from a lot of (largely poor) ticket buyers and profiting big from it. It's the same kind of dynamic as counterfeiting. I'd argue that that's a problem mostly with the lottery system and not with the MIT students' ploy, but they exploited a system with full knowledge of how it operates and how their actions hurt others. That does not come without moral responsibility.

I can't find anything morally wrong about card counting though, Blackjack is presented as a game where skill can affect the outcome, even though in absense of card counting it's a game of luck. I'm sure that a fair number of habitual players develop some kind of card-counting heuristic innately, and in that case people who really count cards (without using some kind of device) are just better players and deserve to win (although I think casinos have good reason to forbid the technique, as the alternative would be to get rid of Blackjack).