What makes a writing Scripture or Canon is an agreement, a consensus of a particular faith community as it looks to past precedent and experience. The Canon of the different branches of Christianity is an example. There some books included in one branch not included in others, though the respective Canons of Orthodox, Anglo-Catholic, and Protestant agree on the vast majority of books.
Just because a book is Canon does not wipe out the tensions within Scripture. Having faith does not require me to ignore paradox. Practically, muting the different voices makes for boredom. The gap between our knowing and doing, our best self and real self, our ideals and the Christian vision, is real. Teaching and preaching that pretends otherwise is a salt that has lost its flavor. **
This diversity of thought can challenge the tendency we have to explain away paradoxes or differences by imposing a uniformity that isn't there. The objective of including all voices is not to diminish, but to allow another voice to inform and transform. Sitting with dissonances is not time wasted. It usually leads to more choice, open doors, and broader horizons.
*See Judges 3-4. Kings 21 tells the story of dogs licking up the blood of King Ahab, and eating (alive?) Queen Jezebel. Ezekiel 16 and 33 contain X-rated descriptions of Israel, Judah, and their enemies. Revelation features images of birds feasting on human carcasses, streets flooded with blood.
**Matthew 5:13 "You are the salt of the earth; but if salt has lost its taste, how can its saltiness be restored? It is no longer good for anything, but is thrown out and trampled under foot."
***The word "synoptic" means to see as one. Mark, Matthew, and Luke are considered the Synoptics. Notably, Mark however, omits Jesus' birth and childhood found in Matthew and Luke.