You miss the point entirely. All of you.
It is illegal to import dangerous drugs into this country while avoiding the FDA, import duties, inspections, verifications of purity, etc.
Just like it's illegal to import Nuclear Weapons, Anthrax and any number of other dangerous items.
Even something as mundane as Cars. You can't just import a Car from -- Anywhere, without going through the proper channels.
And when it comes to dangerous substances, if it's a State Actor and they're doing it in order to harm the People of this Country, that is technically an Act of War.