You were outbid by people who don't look like traditional NZ inhabitants (Māori or European) but that doesn't mean they're foreign purchasers. If they've emigrated to NZ, then they're not foreigners any more, and that couple was just doing what plenty of European New Zealanders I know are doing. Namely, buying a bunch of houses as rentals. (Whether investment properties should be a thing, and whether Capital Gains Tax would curb that, are left to a different discussion)
No, they are foreign nationals. They have a child studying here are and are investing in property while they're over here settling their child in. I agree that once you emigrate they're as much a New Zealander as I. But these people have not.
The only problem I have with foreigners buying property here is that they are not in our economy they take any gains out of our economy. It increases the cost of living here without adding value.
I’m totes down with blocking foreign buyers, for the same reasons as you. I just wanted to note that not every Chinese home buyer is a foreigner. Sounds like you were already aware of that. Awesome!
But they add cash value because the native seller now has whatever amount extra coming from a different economy. It will raise the prices of homes in the area as well. This will fuel growth.