That's trivial, may just be an honest mistake and in no way disqualifies the entire work.
If Dershowitz copied from Peters in excess of fair use then it's a matter of copyright infringement and intellectual property theft which does not involve Mr. Finklestein. It is a matter for Ms. Peters to pursue with Dershowitz's publishers and their attorneys. Again, this in no way invalidates Peters' original work.
All your massive cut and pastes have done nothing to prove that Norman Finklestein is a gentleman or a scholar, or anything else than a hateful, angry, bitter, vindictive son of a bitch.
No, you're absolutely wrong on this point of the cuts and pastes. It is PLAGIARISM as well as coyright infringement. Copyright Infringement is the cause of action, and copyright is the basis of intellectual property right, with respect to any action that Peters would make, if she so elected.
But PLAGIARISM is based on the duties that Dershowitz has, implicitly, to the academic community as a whole, and expressly to his University in particular.
Finkelstein DEFINITELY proved the plagiarism, even if Harvard elected to take no action.