(According to [1], only 1% of Americans are Muslim, and 60+% are Christian--and I would be shocked if 60+% of American film characters are identifiably Christian never mind [how they are portrayed][2])
Worse, this seems to be increasingly prevalent in the academy as well. Indeed, the study cited in the article (from University of Southern California’s Annenberg Inclusion Initiative) also doesn't mention these points of context and the paper is pretty overtly propagandist.
[0]: https://www.huffpost.com/entry/movie-characters-muslim-riz-a...
[1]: https://en.wikipedia.org/wiki/Religion_in_the_United_States
[2]: http://decentfilms.com/articles/hollywood-religion-problem