I don't know enough to have an opinion on marijuana's medical benefits, but in principle at least I agree. Unfortunately, "we live in a society, man," and that society requires that you find some way to transform
I want into
I have no choice before it'll let you do something it feels icky about. There are numerous examples of this that I won't list here because I don't want to digress into other hot-button topics, but I bet you can think of at least two right off the top of your head.
With that in mind I think starting with medicalization was a smart strategic move. The only other options were to make a lot of Americans less controlling, or to convince them that they're wrong, and, well... good luck with either of those.