Privacy is usually not about things you don't want anyone to know. It's about things you don't want everyone to know.
Even if you are not any of those, it is our duty to provide a thicket where the free canaries can hide from the harsh environment. When they die, we best pay close attention.
Saying “I don’t care about privacy because I have nothing to hide” is uniquely selfish, on the level of “I don’t care about gay marriage because I’m not gay.”
(I say this while I agree with your post otherwise.)
Everyone leads a “double life” (or N lives) to some degree, and privacy is the societal etiquette allowing for the continued separation of those lives (without having to go to the effort of using real OPSEC to isolate them.)
Doesn’t this only work if all your interactions are online? Otherwise your family might meet your colleagues at your birthday party (or whatever you might celebrate).
What's your age, sex, and race? These are questions that, in and of themselves, are not private. Any stranger on the street who sees you could immediately answer them. And if you've ever posted a picture on the net, you can add far more people. And you probably wouldn't be bothered if every single person in the world knew the answer to this question. And in fact you've probably told everybody the answer to these questions, even if indirectly, in your own posts.
Yet in spite of all of this, you probably would not want to tell me. And that's largely because I have absolutely no justification in asking or knowing this. If I said I was surveying developers, and you believed me, then you'd probably be more than willing to submit this information to me however.
Google wants to harvest massive amounts of information on me to, at best, try to get me to purchase things I otherwise would have no desire to purchase. And that is, again, at best. This is the same company that literally black-listed the term "human rights" for their proposed engine in China. [1] To imagine they won't, if they are not already, use that information for even more nefarious ends is being naive.
So on this front I couldn't care less if every disinterested person in the world knows what I had for breakfast (it was muesli), yet I would not want Google to have this information, because I don't think they are justified in knowing it. More sensitive information just ends up reaching a higher and higher standard of required minimal justification.
[1] - https://theintercept.com/2018/12/01/google-china-censorship-...
Medical records are another good example. Most people are squeamish about reproductive and sexual health... but share such info with a doctor.
Only if I had made up my mind that I would have no - or only a small - problem with the photo going public. I may conceivably trust the partner. I do not trust partner's ability to keep things under sufficient lock.