i don't think that's how science determines if two things are the same. i think you just made that up because it sounds clever. unfortunately, that's not how things work in reality.
i also don't think you understand that you don't have to smoke pot. you can eat it. in medicine this is called 'oral administration'. you can't just ignore facts you don't like, that's not how medicine and science work.
most drugs are eaten. pot is a drug. you can eat it. you can use drugs to treats disease and symptoms. therefore, you can use pot to treat diseases and symptoms... by eating it.
i don't understand what your mental disconnect is, other than you just don't like the idea of pot, which is fine, but you should just say that, because then it becomes a moral argument, which is what you're trying to have, rather than a medical one, which is pretty black and white - pot is a drug, and you can use drugs to treat diseases and symptoms. that's pretty much a fact. again, i'm not really sure where the disconnect here is for you. this is a pretty simple logical chain. maybe you don't consider pot to be a drug?
i've never met anyone who doesn't think pot is a drug, but i suppose it's possible.
but really i think you just don't like the idea of it, which is a perfectly respectable opinion to have.