I have crohn's, that wasn't very responsive to medication. Cannabis game me my life back, it eliminated the inflammation in my colon, and allowed me to eat without horrible pain prior to my ileectomy.
Many drugs for illness' are band aids, so saying cannabis isn't a cure isn't a good argument. It is one of the better band aids, it fixes a lot with very few (if any) negative side effects.
I now use marinol and a CBD supplement since I'm in a non MMJ state. Cannabis helps with much more than the pain, there are studies on it helping intestinal spasticity. It helps with inflammation, with the caryophylene in it and other aromatic terpenes. To say it doesn't help is to disregard studies and many anecdotal reports of it working for many, many crohn's sufferers.
I feel that marijuana would, if nothing else, be effective in helping Ulcerative Colitis and Crohn's Disease sufferers deal with the pain related to their diseases and in a way that is much less addictive than traditional pain medication such as Vicoden. Marijuana is already used effectively to deal with pain that comes with other disorders.
Marijuana is not a "treatment", but it can help relieve some pains that are suffered by people who have these illnesses. It will not cure these patients, but its use should be allowed because patients who suffer these diseases are in a lot of pain and discomfort and need some relief.