U.S. attorneys warned that even state employees could be subject to prosecution for their role in marijuana regulation.
state workers who are involved in approving and regulating the sale of an illegal drug are also committing a Federal crime.
Banks do not want to get visits [ or worse ] from U.S. attorneys
IMO it is the feds who are committing the crime by exceeding their lawful authority. They require a Constitutional Amendment to act as they do in these matters, and for lack of it they lack legitimacy and lawfulness in their actions.
Dunno about you, but in my life the feds exceeding their authority has far more of an impact than all the dope smokers combined.