There is a famous scathing review by Whittaker Chambers (of the Alger Hiss controversy) that later got accusations that he'd never read it.

Some people who criticize Atlas Shrugged obviously have read it to at least some degree. They may have been skimming, or they might not have had an open mind, but some of the points are always satirisations of some parts of the novel.

Occasionally it's done well. Usually it's just a waste.