As I said previously, I'm all ears awaiting the introduction of a rational principle that would make different considerations apply to marijuana than to alcohol (apart from extrinsic considerations such as legality, etc.). I have never used pot, and therefore have no horse in this race. I did not find the "food stuff" argument by the Novus Ordo "theologian" at all convincing (not to mention that marijuana can be and has been consumed as a food). I don't find that relevant to its morality. Even the question of benefit vs. potential harm is somewhat peripheral (and is medically debated) and is more a practical concern (such as what one might have with cigarette smoking, etc.).
I'm pretty sure that if big pharma isolated THC, put it in tiny doses in some kind of pill, combined it with one or two other ingredients, called it something else, and marketed it for its therapeutic effects, it would therefore somehow get "sanitized" and made acceptable in many people's minds. I feel that this is all about perception, with people having visions of college students sitting around a bong getting high. No one here has ever said that was permissible and not a grave sin. I see no difference in taking small amounts of THC and, say, taking a Xanax for anxiety, simply because the latter was developed by big pharma in a lab.