Apparently hosting this video is part of a violation of the law in New Zealand, population of 4 million.

For Facebook why not just block New Zealand? Looking for thoughtful responses

edit: seems there are reports of New Zealand ISPs blocking very many sites and web services. So for Facebook this is also a compelling option to just block the country and continue business as usual, focusing on important things like those user metrics. Censoring videos is an antiquated law forcing silly compliance burdens.