> People would still show photos to people in other ways.

I suspect this is not the issue or what the parent means by privacy.

Rather, they probably mean specifically that they don't want their metadata enriched photos being made available, without their explicit knowledge or consent, to Facebook the company (and therefore also indirectly to any number of other companies / advertisers).

If Facebook didn't exist, people certainly wouldn't do that! That's purely an unavoidable side effect of Facebook's current business model.