Objectivists quite rightly complain that much criticism of Rand and Objectivism is unfair. For whatever reason people often find it difficult to fairly discuss ideas with which they agree. Most Christians shake their heads when they read Objectivist critiques of their views, I imagine.
Here are a few reasons why I think Objectivism is easy to misrepresent or, perhaps better put, for critics to "overcompensate" in their criticism.
1. Rand is the greatest thinker since Aristotle. While I admit that she is worth reading and even important, some of the claims about her genius and originality are overstated. And is everything Rand said worthy of great praise? I think of Leonard Peikoff's claim that Rand's diagnosis of the streaker at the Academy Awards as a Kantian nihilist as the summit of cultural criticism.
2. Rand is a great novelist and Atlas Shrugged is the greatest work of fiction ever. Like many people I enjoy The Fountainhead but think Atlas Shrugged brought out some of her worst tendencies, such as using characters as a soap box.
3. Rand's style. It strikes me as hectoring in the extreme and does to many others as well. Of course that doesn't mean someone should call her a "fascist" or "totalitarian."
4. Rand's life. Unless Rand's three biographers (Barbara Branden, Jennifer Burns and Anne Heller) got it completely wrong, Rand had a cruel and eccentric side and encouraged what, with some exaggeration, might be called a "cult." Rand's critics might not know the controversy about Rand's character, but aren't they entitled to rely on these books (in particular those written by non-insiders, Burns and Heller)? When Peikoff tells us that Rand's only character flaw was occasionally blowing her top (which he tries to turn into a virtue) aren't Rand's critics justified in concluding that maybe orthodox Objectivism has something to hide?
5. Rand's movement. The denunciations of fellow advocates (Peikoff's attack on Gotthelf's 2000 book Ayn Rand for example), the splits, Harry Binswanger's loyalty oath, the rewriting of Rand's journals and other material (first revealed by Burns) to conform to Rand's reports about herself, etc. make Objectivism look a little eccentric.
6. Altruism. Rand's jeremiad against altruism just doesn't "resonate" with most people. For example, in Burns' book there some discussion of Rose Wilder Lane's interaction with Rand. Lane grew up on the frontier when people just "helped out." She could never understand why all behavior should be motivated by self-interest or why Rand couldn't appreciate the difference between coercive and non-coercive altruism.