i've heard chomsky speak about this. a group of french folks in the audience attacked him for even saying the man should be allowed to speak. he said clearly he disagrees in every way with the holocaust denier -- and always has. his position is one regarding free speech: everyone has a right to speak as a matter of principle. it's up to us to deal with what the say, or ignore it.
i would assume this is his intent regarding the learner affair.
R