Feathers get ruffled for all sorts of reasons. Often without particular cause.
GETS registration has been required for at least the last decade. It isn't 'a recent move.'
The only restriction on reposting material posted to GETS is where it is specifically labelled commercially sensitive or restricted. GETS actually encourages media to register. Here's the relevant part of the Q&A:
Who is a supplier?
A supplier is any organisation or individual interest in receiving notifications of opportunities on GETS responding to tenders or supplying products or services to a public sector organisation. This also includes consultants and contractors. You can register as a supplier to gain public access to information about government procurement opportunities e.g. media, professional and trade associations.
For NZ residents, the site
https://www.fyi.org.nz
provides an easy tool for submitting requests under the OIA and guidance on how to do so. If anyone has a particular concern about the status of documents, I'd suggest requesting the document using this process, and let the vetting process smooth your ruffled feathers.