Data being public (and privacy in general) shouldn't be 'all or none'. The problem is people joining the dots between individual bits of data to build a profile, not necessarily the individual bits of data.

If you go out in public, someone might see you and recognise you, and that isn't considered a privacy violation by most people. They might even take a photo or video which captures in the background, and that, in isolation isn't considered a problem either (no expectation of privacy in a public place). But if someone sets out to do similar things at a mass scale (e.g. by scraping, or networking cameras, or whatever) and piece together a profile of all the places you go in public, then that is a terrible privacy violation.

Now you could similarly say that people who want privacy should never leave home, and otherwise people are careless and get what they deserve if someone tracks their every move in public spaces. But that is not a sustainable option for the majority of the world's population.

So ultimately, the problem is the gathering and collating of publicly available personally identifiable information (including photos) in ways people would not expect and don't consent to, not the existence of such photos in the first place.