Hmmm, not sure what that's doing on the Airpoints site.
Unless there has been a *very* recent rule change, no this does not apply to you if you are still Star Gold on NZ, as your profile suggests. That rule applies only to United and US Airways's *own* elites who, unbelievably enough, have to purchase Club membership if they want to access UA's crappy lounges on purely domestic itineraries, while all foreign *G cardholders get in for free.
This is a key reason why my Air Canada gold status was so useful to me when I spent most of the last five years living in the US