I agree with you that marijuana and some other drugs were made illegal largely out of ignorance.
I am certainly not against testing drugs like marijuana and possibly psychedelics for their benefits. Some tests have shown benefits of them. However, certainly not enough for me to think we should switch to those over drugs that have been shown to work in full scientific trials. Just because of the ignorance displayed by drugwarriors held back research, doesn't mean we should respond to that ignorance by wanting to use it for treatment without research.
As for the FDA, yeah, right now it is the best body that we have for determining if a drug should be available or not. It has all kinds of faults (way much political influence), but abolishing it or ignoring it would be a huge mistake.