Well they fucked up when they used USDT and said it was pegged to the USD (FRN) while creating them out of thin air.

I'm guessing the CFTC stepped in when Tethers went over $2B in a matter of days, they were creating more USDT than the Federal Reserve creates USD.

Federal law prohibits alternative currencies intended to circulate nationally (+ internationally) if they are misrepresented as legal US tender.