Answer: Whenever some “new” gospel is discovered and the media reports on it, there is inevitably someone (scholar, religion teacher, etc.) who comments that this is a representative of a strand of Christianity that was prejudicially refused entry into the Christian Bible because of the protectiveness of those in power who felt their influence would be compromised. But in truth, these were strands of false teaching that sought to use the Christian garb to couch their views so as to compromise the influence of recognized followers of the apostles. So yes, the leaders in place were being protective, but were being protective of their flocks.
None of these “new” gospels, like the “Gospel of Judas,” were really written by the said disciples (of course, Judas would have had to write at the very end of Jesus ministry, when it became clear Jesus would be killed, and then just before he killed himself, if the New Testament evidence is to be believed at all). The Gospel of Judas was written some 150 years after Jesus and was not written by Judas. It purports that Jesus told Judas that he was doing Jesus a favor by having him killed because he was freeing him from the borrowed body of the man, Jesus, so that his spirit could gain the realms of sinlessness. Judas, in this Gospel, is the hero, and Jesus’ favorite disciple, who has the special knowledge that the body is what hinders us from becoming righteous and how to get free from that bondage.
This is a strand of heresy that was circulating very early in the history of the church and was called “Gnosticism” because they taught there was special revealed knowledge (Greek, gnosis) that they were privy to that Christians needed to add to their concepts of salvation. Paul and John both denounce forms of this concept in Colossians and 1 John. The church early on realized how false and misleading this teaching was.
One of the tenets of Gnosticism was that the physical, material world was evil and the source of evil. Thus, the Son of God had to take on either a temporary body (as in the Gospel of Judas) or the appearance of a body (the apostle John seemed to be dealing with this view in 1 John 1). The way to deal with sin, therefore, took on two very opposing paths. One path was to deny the body. This is asceticism (restrict foods, pleasures, marriage, etc.). The other path was to indulge the body. After all, it was not permanent and did not affect the spirit. Paul argues against the ascetic view in Colossians 2 & 3.
The Gnostic religion was averse to the view of Christianity in its emphasis on resurrection. Why, according to the Gnostics, would our bodies need to be resurrected? They’re evil. But that is not the view of Christianity. The body is an important part of who we are, created by God for eternal existence in its resurrected form. Gnosticism has thus always been antithetic to the main tenets of Christianity. Don’t look for new Gospels to be discovered that overturn the truth of Christ. They don’t exist.