I took a trip on the wayback machine and found a fantastic article written by Aaron Dembski-Bowden about canon and what all the various inconsistencies in fluff means. At one point in the article he quotes something from an in-house meeting with
GW's IP manager, "“It’s all real, and (n)one of it’s real.”
My take away is that everyone in this conversation is correct. Here's an appropriate quote from the end of the article:
So, is there a consensus?
Negatory.
There really isn’t.
On one hand, that’s a bit of an emotional kick to the balls. I mean, everything you do will be seen as incorrect by Some Internet Guy, and they have as much right to enjoy 40K stuff as me, you, or anyone else. I don’t sit at my desk, rubbing my hands together, delighting in the fact that I might’ve annoyed Fan #3,974,910 because I said Commander Dude Guyman zigs instead of zags. I sympathise with that irritation. I felt it myself for long enough, and its bitter taste is familiar to me as all the photos of Lily Cole I have on my hard drive.
Forget her. She never, ever replies to my stalker emails.
But on the other hand, loose canon is one of the keys to why 40K has evolved into something so completely awesome.
I’m being dead serious, here. Yes, it can be considered a mark of IP laziness, and yes, I’m not blind to the fact that 20-30 years ago, a lot of 40K’s core concepts were referential half-jokes thrown around by amateur game designers, rather than the underpinnings of a more classic sci-fi setting “envisioned” by ivory tower artistes. But the loose framework has allowed three decades of fresh canon to flood in, filling in the details without necessarily feeling too constrained by what came before. Even as someone who fiercely cleaves to canon at every opportunity, I’m constantly surprised by the sheer amount of white space left open to explore and set up shop.
Within the possibility of endless interpretation lies the potential for freedom. What matters is respecting the source material, contributing to it, and sticking to the theme. And that ties right back into my first column, because no matter who’s writing the details, 40K has some unalterable themes, etched in the stoniest of stone. They’re the key. They’re what matter most.
Get the atmosphere right, and you’re halfway there.
Everyone is equally correct. The Tau are both evil maniacs bent on mind-control and world domination and light filled teddy bears wanting to bring a little order and peace to a war-torn galaxy.
Link if you want to read the article. I liked it:
http://web.archive.org/web/20111126150322/http://www.boomtron.com/2011/03/grimdark-ii-loose-canon/