Insider trading is already illegal (this case proves it). If the problem is under-enforcement, then I agree that better enforcement is the fix.
Banning gambling is a completely separate intervention addressing a different activity, and clearly wasn't required to bring charges in this case.
The tendency of governments to create new laws instead of enforcing existing ones is how we end up with absurdly complex legal systems and the loopholes that come with them.
Until the Commodity Futures Modernization Act of 2000, Collateral Debt Obligations were regulated differently in different states. Some said it was insurance, and thus regulated it like insurance. Some said it was gambling and banned it outright. Instead, regulation was handed to a toothless new agency who got little funding for enforcement and the rest of the world got the 2008 financial crisis.
https://en.wikipedia.org/wiki/Commodity_Futures_Modernizatio...