Haven't really read much in this thread but what I can say is that the legitimacy of the schefuling system is suspect when it's more likely that the scheduling system in the US reflects what was politically expendient for those in power at the time rather than addressing problems in a pragmatic and effective way.
And yeah there is a back and forth between too extremes in the rhetoric between the "harmless" and the "extremely harmful" side. A kind of black and white thinking, where one side is a combination of those who are trying to justify the status quo and those who believe them and the other are those who have discovered that it's not
extremely harmful as they had been told and take to the opposite extreme.
So here's the truth as I understand it. Marijuana is not harmless, but how harmful it is is very
much exaggerated by law enforcement.
One common myth about marijuana from thos who would claim that it isn't addictive. This isn't quite true, the truth is that it's extremely unlikely that one can develop a chemical dependency on the active drugs, the cannabinoids, that naturally occur in Marijuana flowers. Meaning that withdrawal symptoms from quitting are basically bery rare.
However, marijuana can be addictive in a way similar to how gambling or social media use or certain foods high in fat, salt or sugar can be addictive for some. It stimulates production of dopamine in the reward path system of the brain via the canabinoid system which is what is ultimately responsible for the sensations of euphoria that many experience while high (it actually increases the amounts of dopamine released from various sensory stimuli, especially from eating, listening to music and sexual stimulation). While it's extremely rare to have chemical dependency, it's still possible to become emotionally or psychologically dependent on marijuana for things like mood regulation or anxiety management. However, the addiction liability is generally pretty low.
Other risk include psychologically negative reactions to the experience of being high. What effects that marijuana has on a user is dependent on two factors: 1) the strain used and its cannabinoid and terpene profile and 2) the biology of the person using it. On that second part, not everyone is even capable
of getting high, and those who can can't always experience the full range of potential effects. Some people experience certain negative psychological effects including heightened anxiety and low level paranoia, with a very small minority of people even experiencing what's called "marijuana psychosis" a temporary psychotic state one has while high which ends when the high wears off, more likely to happen if the levels of CBD are particularly low in the strain used, and sometimes dependent on the terpene profile as well.
There is also concern that THC in particular might actually be a potential catalyst for the onset of schizophrenia in those genetically at risk for developing it. However there is not much consensus about this as so far this is merely a correlation between the typical onset of schizophrenia in the late teens and early twenties and the age in which most people who try it tend to try it the first time so whether or not this correlation indicates causation is yet unknown, but just in case, it's not reccomended that anyone with a first degree relative with schizophrenia should risk it by trying before the age of 25 or sometime after that.
Oh and one last risk, some people can experience nausea and vomiting after a prolonged regular usages which can be treated with hot showers, eating foods with black pepper and taking a break from regular usage until it passes.
For the most part though, these risks are generally pretty low for most people. The vast majority of recreational marijuana users only use casually without long term problems, and the majority who use it medically for things like chronic pain management and or anxiety/depression disorders do so without experiencing most of these risk.