It's not a literal description of what happened.
Read the article you linked to, not just the headline. It explains the additional factors that informed the decision.
The "1 positive case" narrative is nonsense.
Read the article you linked to, not just the headline. It explains the additional factors that informed the decision.
The "1 positive case" narrative is nonsense.
Nevertheless, it is still a literally true statement that the entirety of NZ was locked down over one (1) case, because if they hadn't found that one case, they wouldn't have done that.