Legalization will likely benefit non-users too. Incarcerating people over what they choose to put into their own bodies isn't free. Tax revenue from legalization is not only not costing us money, but making money to use for society. Also, the risk of a flash grenade being thrown into your home over the possibility of there being a banned plant in the home goes down. I also don't agree with police checkpoints where you have to stop and prove you are innocent. The list goes on. Right now the most dangerous thing about marijuana (and many drugs) is being caught with it.
Please. Being caught with marijuana would be bad to me because of my licensure. Possession of a usage amount of marijuana, in absence of any other criminal suspicion, is exceedingly unlikely to encounter legal attention, and if it does, has very low consequence.
Growing your own plants or distributing, especially across borders, is an entirely different matter.
You are a doctor, do you support alcohol prohibition in an effort to save people with bad livers from making their condition worse? Would you tell someone under your care with a less than healthy liver to avoid alcohol? Or would you push for a ban on all alcohol?
If I were to create a society from scratch, yes, that would not be a substance I would have as legal. But liver disease is not much part of that. More compelling are things like disinhibition leading to, well, suicide, homicide, and drunk driving accidents/fatalities.
Alcoholic liver disease is a consequence of regular and continued use, potentially reversible, and in itself not very impairing until it gets to later stages. If someone attains sobriety, there is possibility of cure through liver transplant. Even if someone is unaware of their risk, there is high likelihood that a healthcare provider can inform a patient of the problem well before any actual medical impairment is noted, and if one stops drinking, that would be the last of it.
For MJ, you do not have to be a chronic or current user to increase your risk of schizophrenia. Evidence suggests even 1 use ever in the past might increase risk. The condition is, in usual course, chronic and unremitting with severe impairment despite treatment and with significant toxicity associated with treatment, 25 years off lifespan, and 10% suicide rate. And users of cannabis are poorly educated on risks, not that education is of much value, since the most common risk bracket is adolescence.
But that's something I care about. There are pros and cons. This is one of the cons. You don't have to care about it.