I couldn't care less if A. Knox is guilty or innocent, but from my advantage point I can probably elucidate a couple of things that the article (not the book) gets wrong.

If an (informed) Italian is faced with a comparison between Italian and American justice practice (not system), s/he is likely to point out to the rampant racism more than the death penalty, which however could be a close second. Also, faced with the task of remembering some of the injustices perpetrated from the American justice system on Italian's ground, they are far more likely to point to the massacre of Ustica, where (probably, but not with certainty) an american missile hit an Italian plane killing 81 people, while the intended target was a Libic fighter flying nearby.

On the innocence of Knox and Sollecito, however, I know that there's at least a major tabloid which is publicizing their innocence, and so it is likely that at least a good fraction of the population is convinced so.