I don’t think it’s a big deal to take a photo in a public place and not blur background faces, esp if they’re small/ way in the background. If you’re somewhere public like outside, a gym, a clothing store, etc, you might end up in the background of a photo, that’s just how it goes. I understand why a poster doesn’t want their face linked to their username and blurs their own face as a separate thing.

And of course a public place is totally different than a semi private space like a dressing room / locker room / bathroom, that’s not ok at all. I hope people a) don’t take photos in those places when there are others present and b) if they do, they cover/blur the entire person, not just the face.