Your post is incorrect.
1. Signing up for the DNC list will NOT increase spam calls. It will stop calls from legitimate telemarketers.
2. Spammers do not "own" the list. It costs about $16,000 to get a yearly subscription to the list, and spammers would rather spend a mere few hundred dollars for a war dialer.
3. What possible business or economic reason would there be for a spammer to buy a list of phone numbers belonging to people who do not want calls?
4. Over the past few years, some 600 phone spammers were sued by the FTC, so there IS litigation!
Those are my facts.
Do you have any facts to counter them, or are you snorting a bad batch?