She is correct.
It seems that one of the problems here goes back many years, when (after intensive lobbying by herbal enthusiasts), Congress exempted natural remedies from the regulations governing ordinary drugs. Normally, if a company invents a new drug, such as an antibiotic, it must demonstrate its safety and effectiveness, and must isolate the active components, and eliminate (insofar as possible) extraneous matter. No such demand are mad for natural treatments. Thus people can market and sell all sorts of dubious, unproven herbs, which would never make it through FDA approval. Drug stores now often have whole aisles devoted to various flowers, roots, leaves and their derivatives, many of doubtful utility.
Marijuana has some components which might conceivably have pharmaceutical use (although probably far surpassed by synthetic drugs), but is now being offered in unrefined state, for dubious purposes. If this were an ordinary drug, the manufacturer would be required to isolate the active part, and prove its safety and effectiveness for specific uses. Marijuana escapes these requirements because it is a natural product.
Whether a drug is natural or not has nothing to do with is effectiveness or safety. The same principles should apply in either case. It is pure superstition to think that what is natural is necessarily good. Nature is not nice! I know: I just watched a gull tearing apart a robin a few days ago. Nature is cruel and unfeeling. In the 1930s, people used to think that radioactivity was good for people, that it was natures cure for all sorts of things. It came from the Earth, so it was thought to be good!
If marijuana is to be used as a drug, then it should be treated as a drug, not as a recreational intoxicant pretending to be a drug.
The most basic question is...
Is drug criminalization found somewhere in Article 1, Section 8 of the Constitution?
It appears on a cursory reading that drug and alcohol use and control are the responsibility of the states.
Of course, THAT horse left the barn decades ago. *sigh*