I don't think it is that simple. Opium is a natural drug that is harvested directly from a plant. Morphine can be extracted from opium with minimal processing

I don't think it is that simple. Opium is a natural drug that is harvested directly from a plant. Morphine can be extracted from opium with minimal processing. Not much different than using solvents to extract THC or DMT. Morphine is an essential drug for medicine. Cocaine is also derived from a plant and is medically important. Both of these are legal for medical purposes. Heroin is illegal for medical use in the United States for political reasons, but is used for medical purposes in other countries. Perhaps for personal use the distinction should be made, but then what of drugs like LSD? Derived through complex chemical processing, but it isn't unlike any of the drugs you support being legal because they come directly from plants. The point is I don't think generalizations can be made about plants being good and "natural" while chemically derived drugs are bad.