Most countries in the world have censorship laws, so please stop with the slippery slope argument.
Posting the video was already an offense in NZ law, under the Human Rights Act 1993 - Section 61 Racial Disharmony, which bans media "being matter or words likely to excite hostility against or bring into contempt any group of persons in or who may be coming to New Zealand on the ground of the colour, race, or ethnic or national origins of that group of persons."
Before that, going back to 1972, there was the offense of "Inciting Racial Hatred". None of this is new or "knee jerk". In fact, to be prosecuted on racial disharmony grounds, it needs the assent of the Attorney General - checks and balances.
Beyond that, any material can be banned by the govt Censor after classifying it objectional, including graphic violence. Even *fictional* graphic violence. Hundreds of media items are currently classified as Banned/Not Approved in NZ, mostly violent pr0n, but some just on the grounds on pure violence.
And beyond those two mechanisms, no, the govt does not "approve" what we watch. As has been the case for decades.