The same goes for terrorists. If you believe terrorist groups are exploiting an unregulated and unmonitored industry such as the online gambling industry, then by regulating it you can see where the money is going and make sure it is not going to fund international terrorist attacks. All that is accomplished by banning it is that the criminals get a stronger grip on the industry.
The ban on online gambling is much like the war on drugs. If marijuana was legalized in the USA crimes related to it would almost go away completely, because it would be sold in stores and it would be controlled, another advantage would be that people would no longer be going to jail for marijuana-related charges, this means thousands of fewer people getting arrested and going to jail every year, which would save us tax money that could be better spent.
