The US was more concerned with protecting their interests in the pacific (namely the Philippines) than any humanitarian concern for China—though certainly they opposed this.

I didn’t mean to make it sound like the hardware was specialized, only that it’s not a prescription for software but rather an entire “medical device.” Existing as a physical object is probably a requirement for their product to qualify as a “Class II medical device,” which then allows them to sell the package for an insanely high price—even if the physical component is just off-the-shelf tech. And while I can see how you might think this is them “withholding” the product, in the sense that it’s not freely available, it isn’t completely inaccessible—at least, not for the people who need it.

A less cynical reason for their strategy might be that the project received funding specifically for the development of a breakthrough medical device. That funding may have included limitations on what they could do with the result of that development, including limitations that prevent them from either selling it directly to the public or from commercial profit (I.e., profit from a source of payment that doesn’t qualify as a medical expense).

There are a lot of medical devices/other types of objects that require a prescription for no particular reason. My doctor once prescribed me a sandal, which was in every way the same as something I could have bought for $5 except it was a medical-ish pale green and 20x the price.

It's not just an app, it's a watch and phone with software pre-installed, and the bundle is designated as a Class II Medical Device by the FDA. I can only assume there's a lot more money in medical devices than IAPs, at least in the US, and to maintain their class they have to require a prescription.