It's both to brainwash people and instill fear in them.

Suggest that which isn't (fiction) to transmute ignorance over that which is (reality) among those who consent to the offer by free will of choice. The brainwashing aspect represents consent to a) ignore reality and b) to consent to "believe" in fiction, which represents all consented to information in ignorance of reality.

If one believes anything; one ignores everything for it. Reality defines itself; every upheld belief defines ones own perception of reality in accordance to the belief (fiction) offered by other ones.