Exchange of money and goods is not "communication" in the sense of "free speech" or "privacy". The state needs to protect my freedom to not be killed by a hitman, be threatened by guns etc.
I am all in for legalizing drugs, but don't pretend that all weapon trade, offering hacking services or other nasty stuff needs to be protected in a free society. Freedom of speech is about inconvenient opinions, not about "everything you can do by communicating with others".
If the fact that communication may be about an exchange of goods frowned on by politicians (even when they are right to frown) means the communication can't be anonymous, then no anonymous speech is possible.
The possibility that any speech may slide into commerce would mean any speech is open to observation.