The DNC list applies to legitmate telemarketers and whatnot. These scammers don't follow that law in the same way that criminals don't follow other laws.
Scammers do not abide by the DNC list - why would they, when all they have to do is fire up the war dialers? They don't NEED a list - they just program their robocalls and dialers to call blocks of numbers. Nor could they buy the DNC list unless they filled out reams of paperwork for the US government, proving who they are, where they're located, company officers, etc, as well as pay thousands of dollars for a list of people who do NOT want calls and would be unlikely to listen to sales talk.