Why is Birkenhead Primary School promoting the Labour campaign

The Birkenhead Primary School Newsletter promotes the Labour campaign launch:

This Sunday Jacinda Ardern and Shanan Halbert will launch Labour’s campaign for the Northcote by election. All local  families are invited. Date: Sunday 13 May; Time: 2:30pm to 4:30pm Location: Birkenhead Primary School hall.

In addition to speeches by Prime Minister Jacinda Ardern and Labour Candidate for Northcote Shanan Halbert, the launch will feature performances from local school children  that reflect the diversity of the electorate.

Did the school promote any other candidate’s launches? A very bad look for a taxpayer funded school to be playing party politics.