Chomsky is interested in power, not semantics. The question "Who invented email?" has a variety of possible meanings, and if you clarify what you mean, the answer follows from the facts. But people don't care what the question means; they care about the prestige attached to the answer. This is more true of Chomsky than of the average person because of his obsession with power. He knows it is an attention-getting question, and he wants to answer it in favor of a powerless underdog who was robbed of his just deserts by well-connected "insiders," because he wants people to see that story everywhere. Therefore Chomsky runs with a particular interpretation of the question and disingenuously says, "The facts are indisputable," when he knows that the facts are the least issue in the dispute.
Chomsky is as much a rhetorician and an entertainer as anyone on the right, though his intelligence and love of underdogs make him a lot more likable than someone like Rush Limbaugh.