He contends that there is little moral difference between chattel slavery and renting one's self to an owner or "wage slavery". (from Wikipedia)
There is just one example, taken relatively randomly.
"Wage slavery" is a completely invalid concept. If I want to work, and somebody wants to pay me a wage, that is moral and proper and free. It's called trade.
Someone who holds a gun to my head to force me not to engage freely in trade with others is immoral and evil.
Clearly, Chomsky has the latter view, unless I'm misunderstanding.
Actual slavery is an institution supported by immorally coercing someone, too, like the position Chomsky is advocating.
So Chomsky's views have much more in common with slavery than the views he criticizes as being like slavery, i.e., trading one's effort in return for payment.
Chomsky claims to be against "unjustified authority," but he is actually a major proponent of force in human relationships.
I can't take someone seriously who makes these kind of blatantly ridiculous statements.
Of course, I am taking this from Wikipedia, not in the full context of what he has actually written. So, maybe he didn't actually say that. Or maybe he actually said it, but proceeded it with, "The following sentence is false." I would need to hear something to this effect before I would consider taking someone seriously who says the thing that I quoted from Wikipedia.
Because what he's said is in the same broad epistemological and moral category as a verse from a holy book commanding people to kill others for religious regions. In other words, completely unrelated to reality, and completely evil.