Creators are often in the wrong about their creations, and the fact that there was no symbolic attempt behind the use of religious imagery in EVA doesn't mean that the series or film carries no figurative, allegorical meaning in its storytelling whatsoever, particularly in the way its characters tend to relate to each other.
I do, however, feel that there are few innate (or, at least, interesting) Christian themes specifically or religious themes in general in any of the works in this franchise, and I find that especially amusing that the Western audience for anime attached itself so strongly to that aspect of Evangelion when there are works of Japanese animation that deal specifically with Western religions in heavily metaphorical ways that languish in obscurity. Ah well.