Not to get high. These apps specifically cite in the description they know the "high time" for different types of weed. They're clearly not for medicinal purposes.
I live in a state that allows medical marijuana. I know several people who have their "green card" as they're called in Oregon.
Tell me, if the purpose of medical marijuana is not to get high, what exactly are you thinking these people are doing with it? I'm honestly curious. Because all the people I know with a legitimate license to posses it for medical reasons buy / grow the same thing the stoners buy / grow. And they use it the same way too. So I'm truly curious to know what they're supposed to do with their buds if the intention isn't to get high.
I know these apps exist on the App Store. Never checked one out myself. But if I needed it for medical purposes, I'd be thrilled to have some apps available to me to educate me on the topic.
I'd also like to re-iterate what a previous poster asked. Can you provide just one single
credible source that talks about the "serious medical problems" caused by marijuana use?
Finally, you could try doing what I do with my children (8 & 13). Monitor what apps that have. I'm not a perfect parent. But I'd rather do my best than let Apple do my job for me. They should provide the App Store. I should be the one deciding which of those apps end up on their devices. And while as parents it's only logical that we'll have different rules and values for our children, I'm certainly not bothered by the fact that my kids might find out that such apps are available. I'd welcome their questions on the topic in fact. It would be a great and natural conversation starter on the subject.
But that's just my opinion. If this truly bothers you, you should contact Apple directly. Because asking here obviously isn't achieving the desired result (I'm assuming you had hoped for more outrage).