Some people are on a mission to destroy the reputation of a said religion or a said religious figure. When it is obvious what they are up to - they should be discouraged but of course in a civilized way. Problem is - in many cases negative publicity makes them and their controversial deed even more famous and subsequently the problem only skyrockets.
Every religion have some biased critics who (for whatever personal reason) make it a mission in their life to work against that said religion in every possible way they can. Maybe they feel threatened by that religion or maybe they do it because there is money to be made!
The writer of this movie is a controversial figure. Anyone attempting to undertake writing and producing a movie based an historical and religious incident should have the common sense to verify details by consulting qualified historians. Did he do that? If not - then his motives are clear.
I doubt it was ever his intention to consult anyone,he’s not very popular with anyone it seems.