Stanley Fish is a very smart guy and like most such people, he occasionally says silly things.
There is this: Stanley Fish Says Free Speech is Not an Academic Value. That is correct in a very narrow sense, in the sense of his imagining a monkish medieval university, relatively insulated from society and politics, seeking knowledge, wisdom, and truth. Modern American higher ed is mostly anything but that.
Really, free speech and crazy debate is a fine tool in higher ed, in scientific research, and everywhere else. The highest value in academia? No. In society in general, surely its good outweighs the bad.