Do you have any more evidence for some of the claims made in those texts than you do for the claims made in religious texts? Read them all as fiction, but they're still culturally significant and a lot can be learned by reading them, even if all you are learning is more about your fellow human's perspective.

The Dao De Jing, Mahabharata, and Plato's dialogues have been or are currently used as religious texts (the former two more then the latter, but the Neo-Platonism is/was a hell of a drug).