Earlier quoted context omitted.
There is a difference between what is said in the constitution and what has been declared as a federal law. For example: meth is very illegal under federal law, and not mentioned in the constitution. You should stop citing the constitution.
The controlled substance act, as applied, is insanely unconstitutional. That's part of the reason why they needed to pass an amendment to ban liquor.
The Wartime Prohibition Act says you are wrong. The 18th Amendment was certainly necessary to both make the policy irrevocable without another amendment, and to give states independent power notwithstanding usual Constitutional limits on state power to enforce prohibition on top of federal power, it is much more dubious that it was necessary for federal prohibition.