So if the FDA approved the use of medicinal marijuana you'd support their decision?
That is such a loaded question, I don't know where to begin.
Let's say the FDA reviewed reports, conducted studies of their own, and found that smoked marijuana alleviated the symptoms associated with "X" disease. Therefore, they approved smoked marijuana for patients with "X" disease. And you're asking if I support that decision? Is that about right?
My answer is, that'll never happen. Smoked marijuana will never be considered medicine.
BUT, if that happened, then yes I'd support it, provided it was implemented like any other drug (a doctor's prescription, dispensed by a pharmacist, specified dosage and frequency for a limited time, number of refills, side effects, drug interactions, legal liability of both doctor and patient for abuse).