Some over-the-counter pharmaceutical drugs are much more harmful than marijuana, but no one bats an eyelid about them being given to anyone, even young children. For example, there is enough paracetamol in a standard pack of 'panadol' tablets (a common pain reliever) to destroy
an adult liver. Of course there are instructions to not exceed the correct dosage, but this is just one example of a drug that is considered 'ok' to be sold everywhere, but, that if misused, could cause death.
So I can't see what the big deal is about using marijuana medically. One thing in it's favour is that, even when misused, it kills a negligible
amount of people as compared with many other drugs. (Last I heard, there were actually zero
recorded cases of natural marijuana causing death, as compared with alcohol's millions of deaths per year, for example). And in case anyone thinks I am an apologist for weed, I'm not; because while it doesn't actually kill
anyone directly, it does, over the long-term, reduce a person's intelligence, motivation and mindfulness, and is best avoided if possible. So of course I would never advocate marijuana being used for recreational purposes...only medical.