I also think the emotional backlash is covering up what Greg is trying to say. If you consume upstream projects, you should value for your own sake contributing to them. Otherwise you have no influence on where they go, it might be in directions unsuitable to your goals forcing you to keep up with an avalance of changes (especially in the case of the kernel - having a feature out of the tree is a major amount of work to keep solid and tested).
That being said, seeing as the first line of defence against Greg's stats were that they didn't include contributions before they consolidated on the @canonical emails for contributions to the kernel. He corrected that, now mdz still complains about the statistics. The best way to prove that they are indeed providing patches would be to point them out. This time the complain didn't even have a point of correction attached, it was just that the stats might be wrong. Sure if they are, let's fix them. If you want glory and fame for your contributions as well as once and for all dispell the "Canonical doesn't give back" accusations then just prove that you do give back in measure.
One good thing that has come out of this whole debate seems to have been Canonical pledging to provide more work upstream. Just the other day they announced the hiring of a team of designers to help with interaction design. I can't wait to see who is on there and what they can do to help us. Aside that their Apport service is pure awesome, I wish though that it could be made more of an upstream project. As a feature it is vastly better than any other bug reporting tool and it helps make Ubuntu very pleasurable to use during their development cycle.