1) Anonymous author for Saint Peter? 2) Continuing a few arguments 3) Responding to Criticism
Sn known on a forum as Pixie has been reading a bit too much Richard Carrier, I'd say, unless it is Bart Ehrman:
The issue of motive is an interesting one. Why would an anonymous author want to pass of his letter as that of Peter? The most likely answer is that the author was a sincere Christian, who felt his letter was important, and perhaps was what Peter would have said, and gave it Peter's name to lend it authority within the church.
It is worth noting that we do have a Gospel of Peter, which, like the letters, explicitly claims to be the work of the apostle. Christianity nevertheless rejects the Gospel of Peter, so the church itself acknowledges that some texts that claim Petrine authorship were not actually written by the apostle.
Similarly, the Apocalypse of Peter is no longer considered canon, although it originally was, despite claiming Petrine authorship.
Elementary, my dear Pixie!
The question is not why an anonymous Christian would want to pass himself off as the Apostle Peter - two works prove fairly well some did or were thought to have done so.
The question is how an anonymous author would succeed in passing himself (as author ego) off as the Apostle Peter.
The rejection of the Gospel and Apocalypse which both bear that name, show that early Christians did have some checks.
Now, saying that the Apocalypse of St Peter originally was canon is most probably not true. There were some rival canons before all the 27 books were complete in one collection, and that one accepted by all the Church.
So, this books never made it beyond one or two local Churches, either because another one knew it to be spurious, or because one had not sufficient proofs for considering it genuine.
And that latter is, considering God has promised to preserve his word and no Church considers Apocalypse as St Peter canon, one sign it is probably not genuine either.
There are various reasons for supposing Peter was not the author of 1 Peter. To start with, the theology is Paul's not Peter's.
Supposing without proof that Sts Paul and Peter had very diverse theologies.
Secondly, there is no mention of Jesus on a personal level. It does, however, mention the "sufferings of Christ and the subsequent glories" in a general way (see also 1 Peter 2:21-24 in particular). It reads as someone who knows Jesus suffered, and is aware of the theology, but not as someone who was there at the time. Even 1 Peter 5:1 ("a witness of the sufferings of Christ, as well as a partaker in the glory that is going to be revealed"), where the author claims to be a witness, there is nothing personal; there is no sense of the author drawing on his own experience.
On tvtropes, there is a trope called "Genre Blindness".
TVTropes : Genre Blindness
There it refers to characters in a plot being blind to the genre the plot is set in.
Most often, genre blindness refers to readers being blind to what kind of work a work is.
You just exhibited that.
A letter of exhortation is not a personal narrative.
It is a letter of exhortation.
St Peter can have had ample opportunity to explain the Gospel in terms of his personal memories and corroborated by Gospels like Matthew and Luke - Mark being their conflation, under his dictation - to the adressees on another occasion.
He speaks to them as if he had known them long enough to know they were going to listen to him.
Suppose he somehow hadn't, he could have decided to depend on their getting actual Gospels from elsewhere than from him, if he was in prison, he might not have had opportunity to write much more.
But the reason why he can't have been in such a position is, if he had been, the guys who got this letter from an unknown person would hardly have taken him for Peter the Apostle, just because he said so.
This type of critique of Christianity is so dependent on early Christianity being essentially an anonymous bookmarket and not a Church.
But it was a Church, and if there was some bookmarket going in, it was not very anonymous. At utmost we don't really know for one of the books (1/27 vs 26/27) whether it was written by St Paul or by St Barnabas. That Epistle is that to the Hebrews.
One can imagine situations in which things either actually get so muddled one doesn't know, or someone over cautious isn't sure even when one reasonably does know it is Saint Paul's.
And suppose it were St Barnabas', and someone was unsure, asked St Paul, and Saint Paul said something like "I endorse it" or "yes, that is exactly what I wanted to say" (when not specifically asked if he had written it himself), and that was enough for it to be canonic and to be probably St Paul's while some circumstance made it possible it just possibly could have been St Barnabas'.
The idea of knowing whether St Paul or St Barnabas wrote it by looking at handwriting is a bit out of hand, since in one place it seems St Paul says he is writing this or that with his own hands. If he specifically says so, it means he was giving his secretary a leave. He might have wanted to give the Church a relic of himself (like those handkerchiefs which people touched his garments with and which healed the sick) and so done it specifically for one occasion.
That means he usually wrote by dictation and that means the handwriting usually was some secretary's.
The idea of someone succeeding to forge a writing by an apostle and get it accepted by the Church, well, why don't you try to forge an order by President Obama (who is still such) or by subsequent President Trump, just to know how easy it is to do so?
I don't think you will succeed, nor would the anonymous Christian you pose as author of the canonic petrine epistles.
Btw, if you really try (don't take this literally, unless you really, really need to) do sth good which will hopefully not be too much resented so you don't get into trouble for it.
Hans Georg Lundahl
Dedication of Basilica's
Sts Peter and Paul in Rome
* On Creationism : Were The Petrine Epistles Authored By Peter?