This comment (https://news.ycombinator.com/item?id=19435419), states that according to NZ law, the video was "born illegal." [1]
[1] term inspired by https://en.wikipedia.org/wiki/Born_secret
Similarly if someone murders someone it's a crime when the event happens, even if it is not found out until later.
In all cases ignorance of the law is not a defence.
And if someone does this from another country then most countries have extradition treaties in place.
I live in the USA. Barring a few very specific categories I'm allowed to post almost anything. At worst I can get sued for refusing to take it down.
> And if someone does this from another country then most countries have extradition treaties in place.
What? I can violate all the New Zealand laws I like. I live in a sovereign nation very far away.
In the grand scheme of things, the murder of 49 people is objectively worse than the rape of a single child.
Facebook shouldn't have a problem getting rid of people who upload this, as anyone who would do so is not the kind of person that Facebook should want as users.
But at the end of the day, Facebook only cares about money.