At the moment, it is jumping onto the Dan Brown-style bandwagon and is asking why such rubbish as The Gospel of Judas did not make it into the Bible. Well:-
1} Check out the dates on these leftovers and most originate in the fourth century although attempted gnostic corruptions can be traced to the first - where it is trounced by the New Testament writers - people who knew Jesus by and large, as well as Paul who experienced Him.
2} The Nag Hammadi 'gospels' reflect this and do not appear in the canon of scripture because they utterly contradict it and have no basis for that contradiction other than the desire to corrupt or control! The joy of the New Testament is that so much of it is clearly personal experience from people there at the time. Naturally enough, they dumped the rubbish.
3} The Gospel of Judas is found in coptic in the 4th century and there is no evidence of an earlier Greek version. Moreover, it contains a Mickey Mouse theology never represented before the second half of the second century.
4} The gnostic 'gospel' of Thomas is part of the Nag Hammadi findings and is certainly very very complete but is all from the 2nd Century when we have considerable evidence of the real Gospels coming from the First Century.
[It is like me writing a fictional account of a day in the life of Disraeli, when I know nothing of Disraeli - and yet my version is accepted as the truth ahead of the writings of genuine historians!]
'Thomas' however is not even a gospel at all. It contains no narrative elements whatsoever and is merely a collection of attributed sayings - some of which might even contain an element of truth - the best lies always do! There is little more effective than quotations used out of their original context. Consider those who have tried to make Churchill into somebody who would have welcomed today's EU. Perish the thought!
5} If God is omnipotent, why would He allow us two thousand years with a corrupted truth? Clearly, all such attacks are from non-believers - those who have failed to experience the Risen Christ. The Enemy is nothing if not subtle.
The main point is this. If, two thousand years from today, a pseudo historian were to find a Book of Mormon, the written ramblings of Kim Il Myung Sun Moon and virtually any example of Watch Tower literature then compare these to the Bible, he could make the same spurious arguments:
"The Church has wickedly suppressed these truths."
The reality however, is that we put rubbish in a bin and do not expect it to be used against us centuries later.