As for the accusation itself, it rests on some pretty weak evidence.  Be rest assured, many people believed David Irving’s books were extensively researched and most of them were not anti-Semites.  That said, it is very unlikely that Chomsky was truly convinced that Robert Faurisson’s book was based on "extensive research”.  He admitted that he does “not know his work very well”.   That said, if he did believe Faurisson’s book was based on “extensive research” it would be more of a backhanded complement than anything else.  Given his assessment of Faurisson’s work he might as well have said this: “Despite years of extensive research, Faurisson, dim bulb that he is, draws all the wrong conclusions.”