The Kiwis is a representation of rugby league in NZ, always has been. David Kidwell tried to 'maorify' the team for whatever reason and this is the reason we lost the Tongans.
I have noticed dating back to when Kearney was coach that the team has become increasingly Maori despite the well-known demographics of who actually plays rugby league in NZ. It may have been a subconscious or unintended consequence of trying to create a certain "culture". It may even have simply been a coincidence that certain "types" of players seem to come from certain groups. One example that always pissed me off was that Kearney spent the better part of 5 years repeatedly trying to phase out Manu Vatuvei for whatever plodder he could come up with to replace him. It seems to relate to wanting "tough, gritty" players rather than "flamboyant, talented" players.
Yeah this is very murky territory but it's also interesting AF and largely goes unmentioned.
However, I don't really know if that's actually what happened with Kidwell, or if it was simply some combination of bad coaching and the unstoppable force of Tongan pride.
As a kiwi and a non-Tongan, I'm happy for the Tongans and for their people to watch their team play here in NZ. They've participated immensely to the success of NZ rugby league over the years.
To me this seems contradictory with the rest of your post.
As you say, New Zealanders (NZ born, NZ raised, NZers through and through) of Tongan ethnicity have played a big part in NZ rugby league.
As a Kiwi, I want these guys, who are my fellow Kiwis, to play for our team. Something has gone wrong along the way that these guys don't want to play for THEIR country.
tbh, if these guys want to be Kiwis in every way except playing rugby league for us, it kinda makes sense for us to stop selecting them and ultimately, stop putting NZRL resources into them?