The following are some notes from the article, Modern Hindu interpretation of the scriptures : Swami Dayānand Sarasvati and S. Radhakrishnan, by Y.D. Tiwari and K.P. Aleaz. (~ Indian Journal of Theology 31 no 3-4 Jl-D 1982, p 175-181.)
I am here recounting the books that Swami Dayananda Saraswati considered to be non authoritative. Saraswati threw out the Tantras as they contained immoral teachings. It was one of the first set of books that he threw out. Next Saraswati threw out the Puranas as they were just a bunch of myths according to him.
Then the Swami found some objectionable teachings in parts of the Ramayana and the Mahabharata and declared those parts to be spurious. (My guess is that he found the polyamory of Draupadi to the 5 Pandavas to be objectionable). The rest of what was left, Dayananda deemed to be of secondary authority.
Fine. I do not think that many today even would argue with that.
Finally, he relegated the Brahmanas and the Upanishads (!) also to a secondary authority level.
So what was left? He found only the mantra-Samhitas or the Vedic Hyms to be a fully authoritative work of God.
~ pg. 176