Probably a combination of a theology that doesn't have much room for doubt or irony, plus wanting to mass market to churches so trying to be as inoffensive and saccharine as possible.
I've seen a few Catholic films from European studios about the saints that recognize the ambiguities and struggle of faith to a greater degree and are good cinematically, ex,
Je m'appelle Bernadette (2011) And as I mentioned,
Blue Like Jazz, the adaptation of the book by Donald Miller and I think may be the sort of thing you are looking for BRTD.
Image Journal has some lists of films that they see as having Christian or spiritual messages:
https://imagejournal.org/read/film/