Why would anyone living in the Netherlands know or care about COPPA? And why would Google enforce COPPA compliance internationally? That seems like a waste of resources, not to mention limiting their audience.
Because it's Google (an American company) who have to comply with COPPA and not some children (of any nationality).
The most efficient (least resources) route of compliance is to add a 13 or older checkbox, and disable anyone who doesn't check it.