The news sites I frequent (including the NYT) don't seem to have put it in a prominent place, so this is the first I heard about it. And yes, it's depressing. Unfortunately, the whole idea that humanity has an intellectual patrimony that should be preserved isn't a universally shared value. (If your basic take is that anything that draws one's attention away from God is a distraction from the only important thing in the world, then it only makes sense to get rid of them. Still more if it might teach untrue beliefs.)

One ray of light: the Washington Post is reporting that while some documents were left behind (either in haste or to keep things looking normal) the staff successfully hid the bulk of the collection elsewhere. http://www.washingtonpost.com/blogs/worldviews/wp/2013/01/29/heres-what-was-in-the-torched-timbuktu-library/ We'll see-- developing stories like this often produce reports that turn out to be false. But one may hope.

(I admit that when it comes to historical materials, I tend to value safety and scholarly access more than any cultural imperative to keep them on site. Not that anyone's asking me.)