Ping to your attention.
This is bad reporting. The Court totally skipped the question of whether the treaty rights are judicially enforceable. The Court only said that even IF the treaty were judicially enforceable, the exclusionary rule wouldn't be an appropriate remedy for its violation. The plaintiff wanted the Court to create something similar to the Miranda rule, meaning if a suspect wasn't read his treaty rights, his confession or whatever would get thrown out. The Court said take a hike.