Because it doesn't provide for a means of distribution. So, good news.
"For example, according to the law, distributors could not receive compensation for medical marijuana, meaning they would have to grow and give away cannabis for free, according to Draskovich. The statute -- which conflicted with other state laws prohibiting marijuana possession and distribution -- also said distributors could possess only enough cannabis for one customer at a time."
So, MMJ is not challenged, it's supported.