Just anonymize them changing to Monero forth and back and there is nothing wrong in that. BTC is just a currency and is neither good or bad. Only using them can be good or bad.
PS. I don't use drugs.
money is also used for buying drugs. but nobody bans using cash.
But fiat can be controled by government.
BTW the biggest drug dealers and drug manufactures are the central governments themselves, disguissed as the medical/pharmaceutical systems and military/law enforcement.
They want control over the populations