He may be alluding to the fact that money laundering is easier to get away with using regular trace-less cash than through an immutable public ledger where your criminal activity is stored in perpetuity.
(The factuality of these claims is not being offered or challenged; only the observation that the justification seems to have completely flipped.)
Money laundering is a place where scale matters. Having the anonymity of cash creates privacy at the individual level but it's scaling issues are actually a feature that limit abuse.