Please tell me you have a link to this because otherwise I'm going to assume you just made this shit up, what with everything else you've said so far being patently wrong an' all.
I can't be expected to memorize the URL of every worthless developer interview, especially since I never pay attention to the hype. Ever. I remember when I first started hearing about Brütal Legend I thought to myself that it was just going to be a horrible, prolonged, incredibly painful Chuck Norris joke with every instance of "Chuck Norris" replaced by "heavy metal".
However, a quick Google search does indicate that other people have read the same interviews and at least discussed them on various forums. Turns out the reason they removed non-linearity was because every person ended up taking the same path in the non-linear versions of the levels. Must have just been one of those behavioral quirks people have. You know, going left whenever you're lost.
Also I am beginning to suspect that you are not very good at mathematics, considering "everything else I've said" was "Left 4 Dead is a serious, serious game". Also I am not in any way accusing anyone in this thread of being a creepy fanboy, but I notice that your clever counter-arguments to "Left 4 Dead is a serious game" were all just either "you are wrong" or "AHAHAHAHAHAHA" (AKA the "crying on the inside because someone said mean hurtful things about the things I like" response)
What was in any way non-serious about Left 4 Dead? Was it something some particularly wacky player said to you in a multiplayer session? Because I've heard stories about that, which I believe to be entirely fictional. This is because the only kind of people I've met online in L4D are the ones that don't communicate at all ever in any way and the ones that treat co-operative online shooters like they were World Of Warcraft progression raids. Which is to say, by responding to everything with a fullblown psychotic episode.