Besides, IIRC in my last post I said that this matter of contraband drugs is not a matter for federalism. It’s of national concern. It requires national resources, which is why we have the DEA.
The Constitution does not authorize the federal government to legislate on all matters that are "of national concern" and "require national resources." The Constitution is a strictly enumerated grant of authority, with all powers not explicitly granted to the federal government being reserved to the states - and among those explicitly granted powers we do not find the power to regulate any drug transaction that does not cross state borders.
And note that your argument can readily be used by libs to justify, for example, Obamacare.