Everything you've said here is effectively worst-case scenario and you are treating that pessimism as skepticism when they aren't the same thing.
So let's be clear on a few aspects of this that are bordering on absurd:
1. The actual incentive for Amazon is building a remote healthcare business. The idea that Amazon is going to somehow force providers to direct you toward "cheap" treatments is asinine. Why in the world would they care? This is entirely separate from Amazon's insurance, which it doesn't own.
2. No they can't. Twice now the premise of your argument is that Amazon is somehow able to dictate what healthcare providers do. They can force a nurse to overstate the dangers of pregnancy? Are you serious?
3. This is either the most naive statement you've made, or a bold-faced lie. I'll assume the former. The treatment itself is provided by Oasis Medical. They are not owned by Amazon. Amazon owns the technology. Oasis owns the care, including, patient records.
I'll agree with one thing you said: people don't understand privacy. This is no exception. While invasive invasions of privacy only require a visit to a website, medical privacy has been default on for decades.
Another thing people on HN don't seem to understand: There is an enormous different between skepticism and pessimism. The latter makes it incredibly easy to ignore the content of your messages as nothing more than a conspiracy theorist. There are probably a sea of valid complaints about this program, unfortunately they get buried under a sea of absurdity that the world outside of HN completely ignores.
It's unfortunate.