Typical of Hollywood to misguide the populace with historical inaccuracy towards Muslims as though we're anti-science, submissive/oppressed, and barbaric.
This movie would have been brilliant if they actually researched. Having factual events in a movie does not result in a boring documentary. It is possible to embellish and include side-stories; however, to re-write historical events is criminal. Imagine if Hollywood made movies about slavery in America and removed all the torture/beatings and replaced it with kinder treatment of their slaves. Inaccuracy is misleading and an evil agenda.
EDIT: If you don't realize why people are upset, it is because of movies like this that have normal folks unconsciously believe false narratives towards cultures and peoples. That information is buried in your mind until it is unearthed with propaganda. Media is without question often weaponized towards your psyche.