And no, Christians were not soley responsible for the destruction of the Library of Alexandria. Julius Caesar and Aurelian might be more to blame, though time and neglect were probably the biggest vandals.
http://www.straightdope.com/columns/read/2233/what-happened-to-the-great-library-of-alexandria
Also, if you're using that "askwhy.uk website as your sole source, I would consider branching out a bit. It's not exactly what I'd consider a rigorous academic resource.
Your source tends to back up my version of events than otherwise. I asserted that Caesar damaged the Library during his campaign in Alexandria. To quote your source:
"Some people therefore blame Caesar for the destruction of the library. However, while the library may have been damaged during this episode, it probably wasn't destroyed. Forty thousand books would only have been a small fraction of the library's collection. A fire in the harbor wouldn't have reached the library proper, although scrolls stored in warehouses might have been burned. The Greek geographer Strabo (64 BC-24 AD), writing during the reign of Augustus, seems to have had some acquaintance with a functioning Alexandrian library. Suetonius, writing around 125 AD, says that the Emperor Domitian (reigning from 81 to 96 AD) used Alexandrian scholars to replace texts from Augustus' library at Palatine after a fire. This is strong evidence that the Alexandria library continued to exist well after Caesar burned the harbor."
I also asserted that Aurelian caused considerable damage. From The Straight Dope:
"The next fire came 300 years later, in 273 AD, when the Roman Emperor Aurelian invaded Egypt as part of his war with Zenobia of Palmyra. Much of Alexandria was burned, including the Brucheion district. Whether this fire destroyed the entire library or whether some portion was rebuilt is not known."
Your own source lays the blame squarely on the Christians:
"As Christians gained dominance in the region, they felt uncomfortable with pagan temples full of pagan documents. In 391 AD, Theophilus, the patriarch of Alexandria, urged a mob to destroy the temple at Serapis, presumably at the same time destroying whatever books were left in the daughter library. This was hailed as a great victory of the Christians over the pagans."
The conclusion of the article is pure apologetics in my opinion. The Christians didn't destroy the Library, despite what our historical sources say. Oh, no!
It was the ravages of time!?! Ridiculous. Your own source supports my conclusion that the Library was destroyed by the Christians more than yours.
As to my use of askwhy.uk, it's not my source, it was the most convenient link that provided a concise account of the historical events under discussion. My source is Gibbon's
Decline and Fall of the Roman Empire:
"The valuable library of Alexandria was pillaged or destroyed; and near twenty years afterwards, the appearance of the empty shelves excited the regret and indignation of every spectator whose mind was not totally darkened by religious prejudice." [Chapter 28]
Gibbon had no doubt who was to blame for the destruction of the library:
"Demolition of the Idolatrous Temples at Alexandria, and the Consequent Conflict between the Pagans and Christians. At the solicitation of Theophilus bishop of Alexandria the emperor issued an order at the time for the demolition of the heathen temples in that city; commanding also that it should be put in execution under the direction of Theophilus. Seizing this opportunity, Theophilus exerted himself to the utmost ... he caused the Mithreum to be cleaned out ... Then he destroyed the Serapeum .. and he had the phalli of Priapus carried through the midst of the forum ... the heathen temples ... were therefore razed to the ground, and the images of their gods molten into pots and other convenient utensils for the use of the Alexandrian church."