Yeah where does he admit he didn't understand how bitcoin works? That's like saying Ross Ulbricht or any other criminal didn't know how it works. If they got caught sending money straight to an address that was tied to the personal name or details then sure, that's ignorance, but there are 100s of ways the law can catch you and not just by tracking the blockchain. Use mixers and protect yourself and they'll be impossible to track. Leave your fingerprints all over the contraband and packaging and they can easy catch you that way.