I may or may not have to start a Non-Objectivists' Ayn Rand Anti-Defamation League. To wit, another piece critical of Rand from Andrew Sullivan's blog.
I don't believe, as the reader claims, that Rand believed in the "perfectability of genius" or that genius is "incapable of making an error." This is indeed a peculiar claim, seeing as how Dagny Taggart spent much of Atlas caught in what Rand considered fundamental errors about the desirability of cooperating with the evil "moochers." We see Hank Rearden undergo a similar evolution over the course of the novel. Without these errors on the behalf of generally positive characters, there would not be much dramatic tension, and the novel would be far less interesting.The Fountainhead is similar; Gail Wynand is a tragic hero not because of his lack of intelligence or industriousness, but because he fundamentally fails to grok the nature of mob power.
Rand did say at various points that the nature of reality is such that contradictions don't exist, and so therefore it's impossible to make errors if one has one's premises right. I'm not sure I actually disagree with her much there. I do think she made a crucial error in estimating how difficult it is to get one's premises right with regard to fundamental questions and how easy it is apply fundamental principle to shifting questions of fact. I therefore agree with Sullivan's reader that Objectivism would have benefited from a healthy shot in the arm of what Sullivan has called the "conservatism of doubt." That said, the reader's criticism takes a sensible criticism way too far. In doing so, he may even commit the same error of which he accuses Rand.