I definitely agree with this. Preventing a new user from posting an observation of a human would just challenge them to get around it some other way.
I’d personally be for hiding photos of observations with Community ID at Homo sapiens (to prevent people/groups of people from hiding legitimate posts by identifying them as Homo sapiens). And I think it would help emphasize that iNat’s not about observations of humans or human detritus.
Adding a flag similar to “Copyright Infringement” would mean another flag that curators shouldn’t resolve if the flag is deemed legitimate. We have a few of those already and it’s not a great setup. An “inappropriate” flag for photos or sounds, combined with functionaliy that allows a curator to hide the photo or sound (similar to how comment work now) might be a more elegant system.