There's a possible confusion here in conflating the processes of distinguishing faces from non-faces and distinguishing between faces.

The claim that it's all hardcoded seems to apply to the second task (there's prosopagnosia -- lack of the specific ability to recognize faces). If Wikipedia is to be trusted, some neuroscientists argue that the ability to recognize faces is actually a learned specialization of a more general mechanism for recognizing very familiar objects (the section with that info is tagged as possibly violating neutral POV so it might not be trustworthy).

The post actually referred to recognizing the face-concept rather than a specific face. I'd guess that this is hardcoded to the extent that people rely on their specific facial-recognition module to alert them to the fact that they are seeing a face at all (hence, facial pareidolia) but people who lose that hardware can probably still learn to recognize occurrences of the 'face' category with their general object-recognition capabilities (quick googling didn't tell me whether people with prosopagnosia can do this).