Unfortunately, these people can use math to hedge their bets and minimize losses causing it to not really be gambling anymore. Long story short... what exactly do they contribute to society? I am not sure, but they are exploiting a loop hole in our stock exchange and making tons of money off of it.
Have you heard of Market Makers? These people get to buy stock at cheaper prices and then sell them at higher prices (like immediately and in broad daylight). They are the ultimate middle men. How do I get into that field?