You're not reading what they're writing. They all were predicting a rapid Israeli victory, within mere days. They believed that Israel could take on all the Arab states at once and still win.
If you want a more colloquial version of the US assessment, this is what Lyndon Johnson told the Israelis before the war (paraphrased in the official US diplomatic records):
“The US assessment does not agree with that of the Israelis: our best judgment is that no military attack on Israel is imminent, and, moreover, if Israel is attacked, our judgment is that the Israelis would lick them.”
If you want a more colloquial version of the US assessment, this is what Lyndon Johnson told the Israelis before the war (paraphrased in the official US diplomatic records):
“The US assessment does not agree with that of the Israelis: our best judgment is that no military attack on Israel is imminent, and, moreover, if Israel is attacked, our judgment is that the Israelis would lick them.”
https://history.state.gov/historicaldocuments/frus1964-68v19...