They are protecting their market. It is only because marijuana was demonised by the FBI during the 30s, that pot has received such a notorious reputation. It is harmless and actually humans have found uses for the hemp plant that makes Cannabis Sativa one of the earliest cultivated plants by humans. Chinese have used it since pre-history and this has spread thourghout Central Asia and further to South Asia where India picked it up. It even spread to Egypt and Middle Eastern civilisations before the birth of Christ. Because of USA and its prohibition, society has lost tremendous amount of knowledge on the use of hemp. Medical is only one area, its can also be used for papermaking, fabircs, rope, sails, and get this - biodegradable plastics. And it is easily grown. A good solution to current pollution and destruction of our planet. Ganja is God's gift to people. The medial professhion should approach this with an open mind. They have been convinced that marijuana has no medical benefit(s).There are currently ongoing clinical trials where marigjuana is used to treat Alzheimer's, multiple sclerosis, seizures, pain (where opioids are used). Best thing is - nobody has ever died from overdose, it is impossible for it to happen.
Cheers!