He actually covers this extensively, but I guess he doesn’t make the explicit connection as to why its nightmarish I suppose.

Basically, the blockchain being very, very public means that anyone and everyone (with the know how, but easy to learn) can access your medical information.

Which, may be benign is you consider good faith uses of the system, but there are so many ways bad actors could use and exploit the information of people they find, and not in incredibly obvious ways.

For example, I find out that you happen to take sleeping pills at night, which put you in a hard to wake sleep (and this makes it easy to do things in your home). Or you are dating someone and they are disturbed that you had cancer at a young age and they don’t really want to “genetically intertwine” with that kind of medical history.

There are just so many ways such information can be used and abused.

And if your counter argument is simply “well just make the block chain private/hard to access,” then you are simply returning to the current status quo (in which are medical history exists on hospital databases that is only accessed by the hospital)