There should be absolutely nothing controversial with that. What I spend my money on that doesn't harm anyone is nobody's business but mine and whoever I'm paying. If it does harm someone, well, that's why we have laws and law enforcement. It's the harm - the crime - that gets punished or penalized. Just like someone who gets drunk and drives. The results can be heinous, so the action is appropriately and severely punished.

Anonymity, or fungibility, doesn't interfere with that. It simply requires that evidence of harm or crime not depend on an abstract exchange of information.