There's a long-running feud between engineering-types and sales and marketing-types, with plenty of mutual disrespect to go around. Among coders, I find that there's a sentiment that great code will speak for itself, or, at the very least, that the salespeople and the marketers are somehow missing the point, focusing on the wrong things, or just plain making things difficult for the engineers by making promised that the development team has to deliver on.
Now, this is a dynamic that plays out in individual organizations, and isn't the case in the anti-Canonical world. Canonical's "marketers" aren't making promises that Linux developers must deliver on, so I think the anti-marketing bias is residual. Or maybe it's resentment that the Linux distro that gets all the glory isn't an engineering powerhouse, but just a re-packager that's riding everyone else's coat tails.
Since one contributor to one of the many independent open source projects that makes up the greater Linux ecosystem is actually contributing to the project as a whole, there isn't that much reason to get all "tribal" about who's doing more than whom, but I think that this particular feud actually has a lot to do about the professionalization of certain open source projects. A large proportion of the serious contributors to Linux are paid employees of companies who are involved in Linux professionally. Their prestige and success is tied up in how well they can portray themselves as leaders in the field. When a company that doesn't lead the pack in code contributions is nevertheless a mindshare leader, it rankles.
This is only an issue if you're looking at Linux advancement as a zero-sum game, though. If there's only so much prestige to go around, then you have to fight over it like hungry dogs. But if Canonical is raising the profile of Linux, then that raises the prestige of everyone who's involved, especially the biggest code-contributors. So, in other words, can't we all just get along?
We also changed the first sentence of this posting to clarify that the advocate or "partisan" was Greg DeKoenigsberg, not David Neary. We didn't mean to imply that the original GNOME census was a partisan endeavor.