I guess they originally wanted to support ISO, but then something happened, and removed the traces from the site.They could not remove from the printed material though.
One reason could be a technical problem - the chip cannot handle all features well, and locks. For example my unit often locks on some ISO’s when FF-ing through some unsupported feature (like multi-angle). When I asked the tech support they suggested to avoid ISO and use some other supported format. 
Another reason could be of legal origin. Perhaps they forgot to buy the ISO licence.
