Disch's review of Clark's biography of Olson is a mean-spirited, vitriolic attack on one of the most important poets of our time.
Disch confuses Olson's life with his verse, implying that since the former was erratic, the latter must be irrelevant. And since he never talks about the verse, he ignores the reason why we might read such a biography.
He relies, instead, on the fact that Olson was not accepted by the "critical consensus of his time," and that any claim to literary fame must be based on a colossal megalomania that forced acolytes to his will.
The "critical consensus" of any time is hardly a reason to dismiss a writer, and if it were, then we should probably stop reading most of the major modernists from Whitman and James to Faulkner, Pound, Stein, Hemingway, Woolf and Lowell, whose "'megalomania" and critical neglect by the critical consensus are part of the record.