"This is ludicrous. How can the fact that somebody does a git rebase make that the preferred form for the code suddenly isn't a tarball anymore?"
Well-stated. I don't know why so many people keep dragging the VCS issue into things.
The complaint was *not* "Red Hat doesn't make their git trees public!"
Why do people insist on pretending as if it was?
It is possible for Red Hat to distribute the kernel SRPMs in a form which unambiguously satisfied the letter and spirit of the GPL without exposing their git trees to the public. How do we know that? Because until recently, they'd spent years doing it.