ProofMode: a camera app for verifiable photography

It depends if the thing you're documenting only exists at a certain location or not. If some bad thing or other occurs in multiple locations, identifying a single location might help identify those known to be present at that location and give clues about the identity of the photographer or people that assisted the photographer.

Also the picture might be documentation of an object rather than an event. Let us suppose that you meet someone who shows you evidence of some bad thing or other that you cannot just take away with you and show to everyone. You might want to withhold geolocation data in order to prevent identifying your helpers who might already be tracked and therefore be easily associated with the published picture later on.

But I think that withholding geolocation data is optional, if I understood the article properly.