I'm not entirely sure where I fall on "snuff films". I have an active aversion to them, yet suspect we lose something by covering up what happens at events like this. The facts of what happened, the real brutality, even how reactions influence outcome. A friend of mine recently tried to share a video of people dying in a night club fire. I chose not to watch it, because I've seen similar in the past. It happens fast, people panic and die or kill others directly because of that panic.
It's sort of like the Jim Sterling video where he showed graphical video game violence, and then a real clip of someone using a pistol to commit suicide in the "fantasy vs real" discussion wrt video games "causing violence". That was really jarring. Will we really be better off for not having access to that insight? I don't think so actually.
Censoring discussion about this guy's motivations I fall soundly on "authoritarian" but that's less a NZ thing and more a general censorship issue.