Kia ora from New Zealand!
I'm from Christchurch and found this website while searching for a mirror of debunking911.com.
I can't add much to the discussion here aside from sharing a local perspective and collating information from local media regarding the event, but FWIW on a per capita basis, the body count here would translate to over 2000 deaths in a population the size of America's.
Unfortunately, the culture of romanticism and zealous belief in conspiracy theories reaches New Zealand also, and this is fast becoming New Zealand's "9/11" (although we don't use mixed-endian dates). There are uncorroborated/anecdotal reports on Facebook of the police disregarding written threats to conduct the attack, that were delivered to the mosque. The gun club the attacker was a member of, was also reported to police, because of overtly radical views and behaviour (doomsday prepping, threats against socialists etc).
There may be failures of the intelligence services here to detect and avert the attack, perhaps not unlike 9/11 (from what I understand of that attack), but such snippets are fuelling speculation and conspiracy. The police and counter-terror response was good from all other accounts. He was taken alive in 30-40 minutes, and is apparently going to try and represent himself in court, probably to try and let out a white-supremacist speil.
Regarding the manifesto, I was surprised by the coherency, but less surprised by the simple, unintelligent white-supremacist views espoused. White-supremacists/Fascists/nazis/the alt-right/whatever-we-call-them-now are known to be active in NZ, I recall a cyclist being killed in a random attack, and many immigrants can recount racism or racial animosity. Which is ironic considering NZ history, all whites being immigrants here for about 200 years, but I digress.
Ipse dixit, the attacker is an "eco-fascist" who distances himself from Marxists and and socialists because he perceives them as being 'anti-white'. He also cites Trump as being an inspiration, but a terrible leader. I think the media are correct to call this person out in plain language as a nazi, fascist or alt-right troll (given his use of memes and N-chan-culture).
What concerns me most, is the only thing I see separating this terrorist from much of the pro-Trump/anti-immigration rhetoric online, is he put his thoughts into action. This may very well be an example of N-chan culture and the conspiracy echo chamber radicalising a person into terrorism.
With that in mind, I would like to say thank you to all the sceptics on this site, for calling out bullshit when you see it, and using actual, non-pseudo-scientific methods to arrive at your conclusions.
Kia kaha (stay strong).