It is a general principle of common law that a contract has to be for a lawful purpose. A set of contracts whose purpose or whose result is to destabilize the currency or the economy is not a lawful enterprise and the Congress is well within its powers to outlaw it. If you think the purpose of these is not to destabilize the economy then you need to go and read the checkered history of Michael Milkin who purposely created the junk bond market with the explicit understanding that the systemic risk that was created would be passed on to the public through the offices of the Federal Reserve who would face the Hobson's choice of bailing out the banks and socializing the losses or else allowing the economy to tank. In other words they held a gun to the head of the US economy and said pay up!
Michael Milken with his junk bonds was like Mother Teresa compared to what Wall Street pond scum have done with derivatives, credit default swaps, and other swaps