With Australia, submarine transport costs to Singapore (nearest 'major' Internet hub) or all the way to North America or Europe for the largest hubs is an order of magnitude more expensive than continental terrestrial transport within North America or within Europe. So that Netflix offers free caching boxes to ISP's meeting minimum traffic levels allows the Australian networks to save substantially on their overall bandwidth costs. It's reasonable for them to zero-rate that traffic as they're effectively passing their cost savings on to their customers, as opposed to trying to double dip by charging content networks for access to their subscribers. This may violate more pure definitions of net neutrality, but should be desirable behaviour as it's pro consumer.

This goes back to the distinction between the real problem, the lack of competition in many markets compared to net neutrality which mitigates situations where there's a lack of competition, but it's not necessarily a win all across the board. What's needed is to separate last mile access, from eyeball network service, from carrier network service, from content network service, from actual content. This would ensure competition across the board, and prevent excessive power accumulated by such a small number of large corporations as is currently the case. However, the nearly religious reverence to capitalism in the US would make such a solution nearly impossible to legislate.