It seems less likely to me that this is Apple being ruthless or pigheaded and more than you really do have to be careful how you market your iPhone apps.
I take your point; the FDA doesn't recognize "snoring" as a medical condition (but OSA is!)
Apple isn't liable for you looking up medical misinformation that kills you using your iPhone on the Safari browser. Why would it be for an app that is clearly made by someone else? The difference is only because of the vetting, and they only do vetting to charge their fee, otherwise they'd vet other things too.
It's incredible how companies bend backwards to bullet proof any liability whatsoever on anything, except if they can make money on it.
They also vet apps to keep garbage and scams out of it.
Many of the things they prohibit are things that are overwhelmingly good for their users: