Considering what happening right now in the world what did you expect? You have people on this site with sons and daughters in the military being killed by people claiming the same "Allah is Great" thing.
Allah is Great has become a warcry. You drew first blood.
What about the Muslims who feel persecuted or oppressed by Christians? Can they make similar comments on Christmas or Easter wallpapers and get your support when the artist complains? What about all the atrocities that have been committed against people in the name of any God or religion? Do we just say 'what did you expect?' because this is the most current conflict?
Sigh.
As controversial as it may seem to some, it's a wallpaper. A work that took some time and should be seen as art. If you want to see it as an expression of faith, fine. It's the ignorant person who doesn't understand that faith or that others have perverted it that always seems to be the loudest and most noticed. The trouble comes when the the rest of the ignorant follow because they think they've found a leader. Hopefully, no one follows the commenter and more people from the community support the artist.
I'm glad it was posted. It really should be a reminder that are healthy expressions of faith among any religion.