Why is it illegal for cancer patients to use hemp/hash/cannabis oil if they decide they want to give it a try?

Well gee, eating rat turds MIGHT cure cancer. Do you have ANY site showiing that it DOESN'T? Everyone knows Rick's little video is BS. If medical marijuana products are used for appetite and nausea, then they aren't illegal. It's never been tested on humans. If it was so promising, there would be all kinds of clinical studies on its effects on cancer, not silly utube homemade videos.