The Bill of Rights prohibits Congress from some powers but is silent on the states using those same powers. Other parts of the Bill of Rights, eg the 2d Amendment, apply to all governments.
Interstate commerce and many other powers of a government are no different. The question is how to build a system of checks and balances and where to draw the line.
I, like you, prefer a much more libertarian approach by eliminating the FDA, and its clones. But to imply that regulation of food, alcohol, pot and cocaine are all the same is ridiculous and make the libertarian argument look ridiculous. There are, in fact, logical differences.
The biggest difference is not in chemistry, but in forcing a situation (extreme libertarianism) on a society not yet ready to accept it.
Forcing libertarianism on an entire non-libertarian society is an act of non-libertarian force just as much as forcing socialism is. We are not going to win by being hypocrites.
Yours for creeping libertarianism, Bob