Allen Esterson in Butterflies and Wheels:
How is it that someone of [Howard] Gardner’s intellectual eminence, a psychologist to boot, can read Freud so credulously, and even come up with the manifest absurdity that Freud presented us with “transcripts” that enable us to judge for ourselves the validity of his alleged clinical findings? The same, of course, may be asked, in more general terms, of innumerable academics and intellectuals in the twentieth century – and the answer is just as elusive. My best guess is that Freud’s extraordinary gifts as a story-teller and rhetorician cast a kind of spell over many readers, so much so that they find it almost inconceivable that what he reports are not authentic accounts of his historical and clinical experiences. There was some excuse (just) for this before around 1980. Thereafter the knowledge that Freud’s accounts of the early history of psychoanalysis were questionable was easily accessible in the literature, and doubts about the accuracy of his clinical accounts were being voiced. Today, credulity exemplified by Howard Gardner’s statement quoted above can surely only be explained by a longstanding attachment to Freud’s writings as a consequence of early acquaintanceship with them (usually in the course of a University education at a time when Freud was almost universally revered in the United States), plus what I’m inclined to describe as a kind of wilful ignorance of the critical writings on Freud of the last three decades. (See, e.g., the bibliography below.)
I would add that self-deception in regard to his achievements, enabling him to maintain an utter conviction as to the rightness of his “cause”, played a considerable role in enhancing the persuasive force of Freud’s writings. As Gellner [1985, p. 216] observed, “the idea that he might be deceiving himself does not seem to have entered his consciousness”. And again Gellner, writing of Freud’s assertion that there was no need for empirical confirmation of his contentions because the clinical evidence was so overwhelming: “This would suggest a person capable of some persisting indulgence in self-delusion.”
I’ll leave Gellner to have the last word. Summing up Freud’s achievements he concluded: “Freud did not discover the Unconscious. What he did do was to endow it with a language, a ritual, and a church.”
More here.