The split mirrors the divide over whether the tech giant should comply with a court order to help the agency unlock an iPhone used by one of the San Bernardino terrorists.
Cook told ABC News on Wednesday that complying with the order would be "bad for America," and set a legal precedent that would offend many Americans.
Yale School of Management Dean Jeffrey Sonnenfeld said Cook "drifted all over the map" during the interview, veering from constitutional arguments to concerns about security, privacy, and creating a slippery slope, he said.
Sonnenfeld told CNBC's "Squawk Box" it was "terrible" for Cook to say that creating a method for unlocking an iPhone used by one of the San Bernardino killers was like creating a cancer.
During the interview, Cook said, "The only way to get information, at least currently the only way we know, would be to write a piece of software that we view as sort of the software equivalent of cancer."
Responding to that quote, Sonnenfeld said, "What he's done is he's resorted to something, forgive me, but close to demagoguery. The definition of demagoguery is what you just heard there, is when you appeal to people's emotions and passions and prejudice over rational judgment."