The princes of Zoan were foolish because they did not take God into account. The so-called wise men of Egypt were not wise at all, and Isaiah expresses disbelief that they could boast of their wisdom. They were utterly unable to help in time of crisis.
11 The princes of Zoan are utterly foolish; the wisest counselors of Pharaoh give stupid counsel. How can you say to Pharaoh, “I am a son of the wise, a son of ancient kings”?