Marijuana* ('medical' or otherwise) is not a "narcotic" under federal law, nor is it considered a narcotic in the medical community.
True... but this term is just a legal technicality. It is still a Schedule I Controlled Substance, which means that you can be prosecuted for possession under Federal Law.
And there are plenty of Narcotics that are legal to possess, ranging from Percocet and Tylenol #3 to Cocaine. As an Anesthesiologist, I administer/prescribe Cocaine on a semi-regular basis... it just happens to be a green colored mint-flavored solution that isn't going to be cut with a blade and snorted with a $100 bill.