Well, there are 2 ineligable players allowed for each NZ S14 team. I think it's being slightly extended with the addition of Argentina to the Tri Nations. There are also guidelines to allow this to happen. I don't see what your problem with this is.
1. Over seas based players are not allowed to play for the AB's.
2. Having someone like Anesi play for the Waratahs, strengthens New Zealand rugby. Anesi would not be able to gain a Super 15 contract with the Chiefs, as there are now better wingers, but he'll still only be eligable for the All Blacks, if he comes to play Super rugby in NZ, while he'll never be able to play for Australia. It's not weakening our player pool and it means more Super rugby experience will come through to the ITM Cup. It also allows some Australian teams, who are low on some options, being able to sign an (other wise unfranchised New Zealander), to help their team.
3. Because of the NZ rules on this, a marque player can not be signed if there is a quality replacement, so our home grown talent is safe, so you won't likely get Giteau playing for the Hurricanes, unless there is no other option (and if there is no other option, Giteau is a good option to have).
I'd rather our players stay in the Super 15, playing for a different franchise and gaining Super 15 experience for the ITM Cup, where they can help develop other players, than them **** off to France, where we'll never see them again of benmefit from them again.