The Justices' Response to the Breqing Case

The court was split on the case, but there were some justices who were obviously skeptical of the plaintiff's argument. How is this an invidious racial classification rather than a political classification? I felt like Kavanaugh made a few comments that felt kind of like a dog whistle. And so it seemed like they were really adopting the framework that the plaintiffs had put forward without understanding why Iqwa and laws that apply to native nations are just different.