From there, it's a basic request to the ISP for subscriber information, and a day or two later the police are seizing the poor schmuck's electronics. If they find christchurch.mp4 or manifesto.pdf, that's a 10 year prison sentence.
Besides that, even if it were a real threat, censoring speech is not the solution. I'm not sure if you have read the Christchurch manifesto, but it's garbage. Seriously NZ is doing the author a favor by censoring it. That way he gets to play the political persecution card and people are less likely to actually read it.
But... we aren't talking about the US?
https://www.macrotrends.net/countries/NZL/new-zealand/murder...
See that big spike at the end there? That's white identity extremism. The deadliest crime in NZ history, the one event that more than doubled NZs murder rate that year, was white identity extremism. It might be a bit of a problem.
Honestly, I don't see what you are trying to point out?
[0] - https://www.rnz.co.nz/news/national/397953/charges-laid-in-3...
[1] - https://www.newstalkzb.co.nz/news/crime/16-year-old-admits-p...