Cook: Security things in Linux v4.13

They have a superiority complex which leads them to believe everyone should just dump their megabytes of patches direct into the kernel without oversight, control or audit.

So it's not really surprising that they were overlooked in preference to others.

Don't forget - just because Google sponsor it doesn't mean that anyone will let it into the kernel no matter what state it's in. And if you're going to sink money on someone on a project intending to get stuff into the official kernel, then PaX basically has zero comparative experience compared to a lot of other people who could do the work.