Hmmm indeed, I would be interested in hearing more on this, or for finding some references to interesting sources about this.
Later I'll give a batch of reliable references - you can always start by looking at Finkelstein's homepage
here - you'll see he publishes most of the articles and letters that are sharply critical of him as well as those praising his work. The Wiki pages on Finkelstein and the Dershowitz-Finkelstein affair are unreliable, as they are forever being changed drastically by people trying to unduly weight them one way or another. But the extra links at the bottoms of those pages are worth following up.