You’re not ‘doing’ anything to someone by taking a photo in public with them in the background. You don’t have reasonable expectations and it’s fine for reasonable people to disregard them.

It's one thing to shove a camera in someone's face. It's another for people to have any reasonable expectation of not getting into even the background of a photo when walking down a city street or in some other busy place.

Well, yes. I'm not touching you right now.

And if you're offended by that, you are being egregiously unreasonable. Exactly the same is true of the picture-taking "concern".