Right, but if you had data that were just that confidential to you, that's the easy part. Just encrypt it and don't let anybody look. I don't really have that kind of data, but I do have a lot of stuff that's just private, in the sense that I don't have anything to hide, but I close the door when I'm in the toilet. So, really private data, encrypt it, store copies in many safe places, you're done.
That's not really what Solid is about. Solid is not just about me, it is about us. The stuff we do together. The sharing we do, but we share not just with anybody, but with someone we trust. It may be something really trivial: I share my grocery shopping list with my wife. It is not sensitive by any means, but it is also nobody else's business. Those are data used on my terms. Nobody should be peeking into my life to map me, as I go along with my daily business, but my daily business consists of interacting with a lot of people, and I do share and I want to share, but I want personal data control.
Now, personal data control is really the key to permissionless innovation. So, we're not just doing it to protect from snooping, once people have their data then you get a level playing field were there can be competition for the best user experiences.