In this case, no insiders broke the embargo. It was reverse engineered from the patch by an unrelated third party and a proof of concept immediately came out of it. At that point, it's kinda fair game.
Especially for a project like the kernel, there's no reasonable way to decide who out of thousands of interested parties should have access first.
Android is a rare exception, as of a few years ago they started a program where phone manufacturers get very favorable early access to AOSP code 4 months ahead of public release.