As usual, Roger Ebert is much more considerate. His review of The Human Stain begins with the following disclaimer:

"The Human Stain" contains a significant secret about one of the characters. This review discusses it. "There's no way we can contain the secret, and we're not even trying to," the film's producer, Tom Rosenberg, told me at the Toronto Film Festival. "It's out there already with the Philip Roth novel. And this isn't a movie like 'The Crying Game,' which is really about its secret."

Well, maybe. But this still doesn't excuse reviewers from blowing the secret for viewers who haven't read the novel (or those who began but never finished it, like me).