I agree with what you're saying. The original impetus for the music is the most determining factor, especially with film music, and if it is successful in that regard, then it is good from an objective standpoint. Not necessarily good to listen to isolated, but good in achieving its purpose.
As has been pointed out elsewhere on this forum, sometimes simple, even simplistic music can be absolutely perfect for a scene, whereas a brilliantly developed symphonic movement filled with masterful counterpoint and excellent voice leading can be completely inappropriate and nothing more than a demonstration of irrelevant skills of a composer completely out of touch with the film.
As has been pointed out elsewhere on this forum, sometimes simple, even simplistic music can be absolutely perfect for a scene, whereas a brilliantly developed symphonic movement filled with masterful counterpoint and excellent voice leading can be completely inappropriate and nothing more than a demonstration of irrelevant skills of a composer completely out of touch with the film.