Hi Will, thanks for your thoughtful comment.
I’ll make an edit to reflect what was an oversight regarding the word “requirement” — you’re right, it’s an option.
With regards to your other remarks, I think perhaps there was some confusion — likely my fault, as I perhaps wasn’t clear in my writing.
I wanted to focus attention on when we *willingly* share our health info, specifically on platforms designed with ad revenue as their base (the key bit being “we invite friends, family, and followers to see the numbers, to track our progress — to share in our surveillance.”) I see now that I ought to have emphasized this more. It was not my intention to suggest there’s an automatic backdoor in some of these devices, just that the information they gather, when shared, works into the creation of a data double.