This that you complain of has long been the same, see C.S. Lewis' essays On Criticism (not published until 1975 but must have been written earlier, probably sometime in the 50s) https://www.catholicculture.org/culture/library/view.cfm?recnum=9115 and an address in 1959 to Cambridge theological students (which has been published under various names) https://orthodox-web.tripod.com/papers/fern_seed.html
(A) from "On Criticism"
"1. Nearly all reviewers assume that your books were written in the same order in which they were published and all shortly before publication. There was a very good instance of this lately in the reviews of Tolkien's Lord of the Rings. Most critics assumed (this illustrates a different vice) that it must be a political allegory and a good many thought that the master Ring must `be' the atomic bomb. Anyone who knew the real history of the composition knew that this was not only erroneous, but impossible; chronologically impossible. Others assumed that the 'mythology' of his romance had grown out of his children's story The Hobbit. This, again, he and his friends knew to be mainly false. Now of course nobody blames the critics for not knowing these things: how should they? The trouble is that they don't know they don't know. A guess leaps into their minds and they write it down without even noticing that it is a guess. Here certainly the warning to us all as critics is very clear and alarming. Critics of Piers Plowman and the Faerie Queene make gigantic constructions about the history of these compositions. Of course we should all admit such constructions to be conjectural. And as conjectures, you may ask, are they not, some of them, probable? Perhaps they are. But the experience of being reviewed has lowered my estimate of their probability. Because, when you start by knowing the facts, you find that the constructions are very often wholly wrong. Apparently the chances of their being right are low, even when they are made along quite sensible lines. Of course I am not forgetting that the reviewer has (quite rightly) devoted less study to my book than the scholar has devoted to Langland or Spenser. But I should have expected that to be compensated for by other advantages which he has and the scholar lacks. After all, he lives in the same period as I, subjected to the same currents of taste and opinion, and has undergone the same kind of education. He can hardly help knowing—reviewers are good at this sort of thing and take an interest in it—quite a lot about my generation, my period, and the circles in which I probably move. He and I may even have common acquaintances. Surely he is at least as well placed for guessing about me as any scholar is for guessing about the dead. Yet he seldom guesses right.
...2. Another type of critic who speculates about the genesis of your book is the amateur psychologist. He has a Freudian theory of literature and claims to know all about your inhibitions. He knows what unacknowledged wishes you were gratifying. And here of course one cannot, in the same sense as before, claim to start by knowing all the facts. By definition you are unconscious of the things he professes to discover. Therefore the more loudly you disclaim them, the more right he must be: though, oddly enough, if you admitted them, that would prove him right too. And there is a further difficulty: one is not here so free from bias, for this procedure is almost entirely confined to hostile reviewers. And now that I come to think of it, I have seldom seen it practiced on a dead author except by a scholar who intended, in some measure, to debunk him. ...It is in fact quite clear that there is one impulse in your mind of which, with all their psychology, they have never reckoned: the plastic impulse, the impulse to make a thing, to shape, to give unity, relief, contrast, pattern. But this, unhappily, is the impulse which chiefly caused the book to be written at all. They have, clearly, no such impulse themselves, and they do not suspect it in others. They seem to fancy that a book trickles out of one like a sigh or a tear or automatic writing."
(B) From the 1959 address:
"What the value of such reconstructions is I learned very early in my career. I had published a book of essays; and in the one into which I had put most of my heart, the one I really cared about and in which I discharged a keen enthusiasm, was on William Morris. And in almost the first review I was told that this was obviously the only one in the book in which I had felt no interest. Now don't mistake. The critic was, I now believe, quite right in thinking it the worst essay in the book; at least everyone agreed with him. Where he was totally wrong was in his imaginary history of the causes which produces its dullness.
Well, this made me prick up my ears. Since then I have watched with some care similar imaginary histories both of my own books and of books by friends whose real history I knew. Reviewers, both friendly and hostile, will dash you off such histories with great confidence; will tell you what public events had directed the author's mind to this or that, what other authors had influenced him, what his overall intention was, what sort of audience he principally addressed, why - and when - he did everything.
Now I must record my impression; then distinct from it, what I can say with certainty. My impression is that in the whole of my experience not one of these guesses has on any one point been right; that the method shows a record of 100 per cent failure. You would expect that by mere chance they would hit as often as the miss. But it is my impression that they do no such thing. I can't remember a single hit. But as I have not kept a careful record my mere impression may be mistaken. What I think I can say with certainty is that they are usually wrong.
And yet they would often sound - if you didn't know the truth - extremely convincing. Many reviewers suggested that the Ring in Tolkien's The Lord of the Rings was suggested by the atom bomb. What could be more plausible. Here is a book published when everyone was preoccupied by that sinister invention; here in the centre of the book is a weapon which is seems madness to throw away yet fatal to use. Yet in fact, the chronology of the book's composition make the theory impossible. Only the other week a reviewer said that a fairy-tale by my friend Roger Lancelyn Green was influenced by fairy-tales of mine. Nothing could be more probable. I have an imaginary country with a beneficent lion in it; Green, one with a beneficent tiger. Green and I can be proved to read one another's works; to be indeed in various ways closely associated. The case for an affiliation is far stronger than many which we accept as conclusive when dead authors are concerned. But it's all untrue nevertheless. I know the genesis of that Tiger and that Lion and they are quite independent."