Weed is not a drug
According to 30% of the population of /weed/, marijuana is apparently not a drug because it grows from a plant. By this logic, people shouldn't think of morphine as a drug, either. Or even datura, for that matter. People who believe any of these things are retarded and should probably visit /chem/ for immediate re-education. While very commonly used by uneducated retards, the "weed is not a drug" argument actually stemmed from the belief that marijuana is such a mild and safe psychoactive in comparison that it doesn't deserve to be even compared to heroin, meth, coke, ect. Caution: visiting /chem/ may result in rape by neckbeard.
Research
Researchers continue to investigate this fascinatingly profound claim. Spoiler: just because it is grown in nature and not synthesized by humans to turn it into the drug we all love (chemical processing is needed to make cocaine, heroin, LSD etc.) does not mean it is not a drug; a drug is something that alters your physiology or psychology when ingested. If marijuana does not do that for you, you're doing it wrong. Nota bene: In the United States of America under federal law a "drug" is defined in Title 21, Chapter 9, subchapter 2, section 321, paragraph "g". According to this definition, marijuana is a "drug" unless it is eaten, in which case it is "food" (as per paragraph "f"). However, this is all irrelevant to the legal status of weed because the Controlled Substances Act regulates "substances", NOT "drugs". In other words, the quality of the substance is more important than the word used to describe it. Put another way, even if weed isn't a "drug" it is still illegal, and people will still oppose the legalization of marijuana.