Article pitches aren't all inherently bad ideas for articles either. A good example from my industry that I'm pretty sure was from a pitch is this one from the WSJ [1]. The basic concept of regaining focus at work is a strong one that resonates with people right now, but all the blog post ends up being is an ad for the product.
My guess is that since people don't pay for subscriptions and rarely click on ads, Wired and some other publications make most of their money now from paid promotional 'journalism'. I would rather have that than nothing. Everything costs money.
This is more likely a case of Facebook "pitching" the story to Wired than Facebook paying Wired to run a paid promotional story. If you don't bite and do a story about the new Facebook thing, all of the other outlets will and you lose out on those potential readers. Because there are so many potential different outlets for where people can read about these bits of news, the PR people have the upper hand under the current views-based model.