This just proves my point.
Does it?
Did you know that the New Testament canon was not finalized until the mid fourth century, when St. Athanasius, who led the anti-Arian movement at the Council of Nicaea and was instrumental in drafting the initial version of the Creed, published the current New Testament canon used by everyone for the first time? Before that time, bibles were being made with many additional books (see the Codex Sinaiticus or Codex Alexandrinus) which usually had 1 Clement and the Shepherd of Hermas which are authentic but Patristic rather than Apostolic, and 2 Clement and 1 Barnabas which are spurious, and also the Epistle of Paul to the Laodiceans and 3 Corinthians, which are also spurious. The Syriac Peshitta had a 22 book canon that reflected the more conservative approach taken by some bishops of the time (and also the fact that not all of the above had yet been translated into Syriac Aramaic and there was a desire to focus on the basics), which was lacking Jude, 2 John, 3 John, 2 Peter and Revelation.
Since the same people who were at the Council of Nicaea either developed the New Testament canon or went on to leadership roles in other churches that would accept the Athanasian canon, it is illogical to argue against the idea that the council itself is an integral part of the Christian faith.
Oh, also, the four canonical Gospels were not even recognized as such, canonical, until the second century. St. Irenaeus was a primary advocate of there being four and only four Gospels and stressed the identification of the Evangelists with the four winged animals we find in Ezekiel and Revelation (the winged man being St. Matthew, the winged lion being St. Mark, the winged calf being St. Luke and the Eagle being St. John the Beloved Disciple). There were other Gospels, some of which were heretical, but others that were regarded as legitimate albeit lacking in important content (the Aramaic language Gospel of the Hebrews, which survives only in quotations), and the Gospel of St. Peter was regarded favorably by some, a fragment survives that had been respectfully buried with a Coptic monk and describes the Passion of our Lord in a normal manner, more or less, although the resurrection narrative is … unusual, but some suspected it of being heretical or docetic, and one bishop made a point of removing it wherever he found it. We also have the Gospel of Thomas, which might be a corrupt Coptic translation of an Aramaic sayings Gospel used by St. Thomas the Apostle and his disciples, a record of the sayings of our Lord, since most of the sayings attributed to him can be found in the synoptics, but the opening of the Gospel makes references to secret knowledge, which suggests the work was corrupted by Gnostics, and certain of the sayings are consistent with what one finds in other Gnostic psuedepigraphical “gospels” like the “Gospel of Judas”. There was an especially blasphemous “Infancy Gospel of Thomas” which based on a remark by an early church father was likely distributed by a follower of the Persian false prophet and heretic Mani, who attempted simultaneously to infilitrate and take over Christianity, Zoroastrianism, the Pagan cult Hermes Trimegistus in Egypt, and Buddhism in India, which was pretty audacious, and the Sassanian Persian emperor gave him a big boost by having him flayed, which made him a martyr, and as a result his religion stuck around for probbably a millenium, and there are two surviving Manichaen temples in China disguised as Buddhist temples, albeit as far as we know no Manichees have used them for nearly a millenia, but they can be identified as Manichean rather than Buddhist by certain abnormalities in the way the Buddha is depicted and certain inscriptions, and this insidious approach of dissimulation was practiced by that religion, indeed mastered by them (it was later adopted by the Muslims). Unlike Christians, who tended to be open about their faith and in many cases, such as St. Anthony the Great, sought martyrdom, in St. Anthony’s case unsuccessfully (the Romans ignored him even when he inserted himself into a group of martyrs being marched to death and tried to get the soldiers to arrest him, but got pushed aside, so he moved on to a different form of martyrdom), most Gnostics preferred to go into hiding like cockroaches, since they did not value martyrdom, and the Muslims adopted this and combined it with the idea that dying in battle for Islam is martyrdom, which of course has given us homicide bombers and so on, and makes the extremist militant Salafi Islam of the Islamic State and other terrorist groups essentially a death cult.