Right up front, some of these guys are making a good point. To read the text through the lens of later theological developments winds up ignoring what the text is actually saying. So in some sense, they are (at least on the surface level) trying to be faithful to the reading of the text as it stands.
But some of them go further: the text, they conclude, doesn’t contain any of those things that later theologians noticed. Some are quick to add some note about the importance of tradition but they do so to point out what they see as a deficiency in relying on Scripture as ones ultimate guide.
In so doing they suggest, without being explicit, that these doctrines originated in a vacuum filled only by necessity. A teaching arose, a response had to be formulated, a doctrine was created. But, it wasn’t Christ’s Deity ex nihilo and I think history proves that. The teaching arose and was recognized as aberrant exactly because there was something substantial already in place.
If you recall, the council of Nicaea was in 325 AD. But jumping solely to Nicaea leaves one ignoring years choc-full of declaring Christ as the Divine God.
So here’s a sampling of early church writings I’ve found that underscored the understanding that Christ is God.
Hippolytus, Treaties on Christ and Antichrist 230 AD
Now, as our Lord Jesus Christ, who is also God, was prophesied of under the figure of a lion, on account of His royalty and glory, in the same way have the Scriptures also aforetime spoken of Antichrist as a lion, on account of his tyranny and violence.
Hippolytus, Fragments from Commentaries on Scripture
By the Ancient of days he means none other than the Lord and God and Ruler of all, and even of Christ Himself, who maketh the days old, and yet becometh not old Himself by times and days.
Clement of Alexandria, The Instructor Book I 195 A.D.
But our Instructor is the holy God Jesus, the Word, who is the guide of all humanity. The loving God Himself is our Instructor. Somewhere in song the Holy Spirit says with regard to Him, “He provided sufficiently for the people in the wilderness. He led him about in the thirst of summer heat in a dry land, and instructed him, and kept him as the apple of His eye, as an eagle protects her nest, and shows her fond solicitude for her young, spreads abroad her wings, takes them, and bears them on her back. The Lord alone led them, and there was no strange god with them.” Clearly, I trow, has the Scripture exhibited the Instructor in the account it gives of His guidance.
Clement of Alexandria, The Instructor Book III
For the Word Himself is the manifest mystery: God in man, and man God
Irenaeus, Against Heresies 180 A.D.
For it was for this end that the Word of God was made man, and He who was the Son of God became the Son of man, that man, having been taken into the Word, and receiving the adoption, might become the son of God. For by no other means could we have attained to incorruptibility and immortality, unless we had been united to incorruptibility and immortality.
Again, that it should not be a mere man who should save us, nor [one] without flesh—for the angels are without flesh—[the same prophet] announced, saying: “Neither an eider,(1) nor angel, but the Lord Himself will save them because He loves them, and will spare them He will Himself set them free.” (2) And that He should Himself become very man, visible, when He should be the Word giving salvation, Isaiah again sap: “Behold, city of Zion: thine eyes shall see our salvation.” (3) And that it was not a mere man who died for us, Isaiah says: “And the holy Lord remembered His dead Israel, who had slept in the land of sepulture; and He came down to preach His salvation to them, that He might save them.”
Since, therefore, the Father is truly Lord, and the Son truly Lord, the Holy Spirit has fitly designated them by the title of Lord.
Melito, On the Nature of Christ, 160 A.D.
For the deeds done by Christ after His baptism, and especially His miracles, gave indication and assurance to the world of the Deity hidden in His flesh. For, being at once both God and perfect man likewise, He gave us sure indications of His two natures: of His Deity, by His miracles during the three years that elapsed after His baptism; of His humanity, during the thirty similar periods which preceded His baptism, in which, by reason of His low estate as regards the flesh, He concealed the signs of His Deity, although He was the true God existing before all ages.
Justin Martyr, Dialogue with Trypho, 150 A.D.
And I wish you to observe, that they have altogether taken away many Scriptures from the translations effected by those seventy elders who were with Ptolemy, and by which this very man who was crucified is proved to have been set forth expressly as God, and man, and as being crucified, and as dying; but since I am aware that this is denied by all of your nation, I do not address myself to these points, but I proceed to carry on my discussions by means of those passages which are still admitted by you.
And that Christ being Lord, and God the Son of God, and appearing formerly in power as Man, and Angel, and in the glory of fire as at the bush, so also was manifested at the judgment executed on Sodom, has been demonstrated fully by what has been said.
Ignatius’ Epistle to the Philadelphians (105-115 A.D)
If any one says there is one God, and also confesses Christ Jesus, but thinks the Lord to be a mere man, and not the only-begotten God, and Wisdom, and the Word of God, and deems Him to consist merely of a soul and body, such an one is a serpent, that preaches deceit and error for the destruction of men. And such a man is poor in understanding, even as by name he is an Ebionite.
Obviously I didn’t include every ante-Nicene Father but that is rather an issue with space than lack of finding. After all, Tertullian, a pre-Nicaea writer who I didn’t quote, first coined “Trinity”!
But the point here was not only to show that the deity of Christ wasn’t a novel idea, but that it goes right back to a disciple of a living apostle: John. So either these ideas suddenly started to percolate after his death or it was exactly what the apostle had been teaching.
For that, we’ll have to examine John’s teaching.