This is not a 1:1 comparison at all, but I can expand on some related import / buy / sell nuances.
Obviously I don't want to get too specific, but I've been involved in investigations (in a civil capacity) for various luxury brands that pursue counterfeiters of their IP in China and the U.S.
Lets use a counterfeit Rolex as an example of the differences of what is an illegal act, what is prohibited, etc
- importation of a fake Rolex is prohibited
- but, attempting to import the item is not a criminal act. The item is seized and that's it.
- once it is past the port of entry and you have it, it can't be seized.
Meaning, if the item prohibited from importation is discovered at a port of entry it can be seized. But you attempting to bring it in is not a crime. (Obviously there is nuance here- if you are involved in selling thats a different story)
It's not a crime to purchase a counterfeit Rolex. It's not a crime to possess or own one. It is a criminal act to sell a counterfeit Rolex, even one. Even while it was not a criminal act to attempt and successfully import that same watch (even though it is prohibited). Get it?
(I wont get into manufacturing as thats not relevant to the U.S., with 99.999% of counterfeit watches being made in China. There was one prolific American counterfeiter for over a decade but he stopped before being properly pursued and now has a legitimate brand)
Then there are the civil actions one could face for manufacturing or selling a counterfeit Rolex.
As you can see there a number of nuances to the law / regulations surrounding importing / buying / selling certain products. One act might be illegal, another act might just be prohibited but not criminal, and another not prohibited and not criminal. All involving the same item. Then, you can face civil actions, or not.
Determining where your product / substance and your actions fall under federal code is not simple for a novice, or even an attorney if they dont specialize in these things.
Having said that, I have no idea what the correct answer for this issue is.