The central tenet of deconstructionism and other literary theories that were trendy during the 1980s and 1990s was that language is so inherently slippery it can mean almost anything. The result was to elevate the critic to imperial status, able to say he or she wanted about a book and freely inject his or her biases, political views, and peeves and crotchits into the text because, according to theory, there was no way to disprove it. Anyone who pointed out that the words on the page said nothing even remotely resembling what the critic claimed could be defamed as a tool of the establishment who was not hip to the secret meanings unlocked by the critic.
It is not surprising that theories such as deconstructionism would attract amoral and mendacious people. Morality ordinarily puts a brake on what such people may say and do, and theory freed them from these restraints.
This book describes the rise and fall of Paul de Man, who became an academic celebrity before it was revealed that he had worked as a Nazi flack/propagandist during World War II. Even after the truth came out, de Man's acolytes claimed that it wasn't true, and that he was the victim of vicious politically-motivated attacks.
It is an interesting and worthwhile cautionary tale. The author, who was on the scene at the time and apparently knew at least some of the main figures in the story, sometimes gets caught up in the personal back-and-forth to the detriment of the larger story. However, that story is well worth reading.
Incidentally, I am informed that deconstructionism and its contemporaries no longer are in fashion among university-based literary critics. I feel confident, however, in inferring that they have been replaced by other equally pernicious theories. Some things have not changed, and, unfortunately, one of those things is the entrenched left-wing academic culture which was responsible for this story in the first place.