The sense of desperation came from having everything cut off.
Between 40% & 50% of Japans imports/exports were carried of foreign flagged ships. The embargos cut the flow of material in and out of Japans ports by nearly half. That alone was the economic equivalent of fire bombing the cities.
For example, Japan had large coal deposits at hand on the Asian mainland, but the number of ships for moving it to the industrial site on the home islands was wholly inadaquate. French Indochina was a major rice exporter, but Japan was rationing rice in late 1941 because there were not enough ships. Tin ore and raw rubber were in large supply in Annam as well, but again...
Japan had no reserve capitol & depended heavily on loans from US & London banks to pay for imports, industrial investment, and pay for imports. It was not necessary to enforce the embargos with diplomacy or threats and pressure. Japans cash flow was wrecked & it could effectively pay for nothing of significance. Even if the Peruvians, Dutch, Soviets or any other had wanted to trade something to Japan they would be taking a bad check in return, or trying to barter stuff for which the primary market would be the US or Commonwealth.
No more industrial tools or chemicals, steel, aluminum, ect.. from the rest of the world. Bottom line here is the US & Britain could have left oil off the embargo list & Japan would have been in the same depth of trouble. Its tanker fleet had 40 odd blue water transports & and another 20 coasters, fleet oilers, and harbor hulks for local movement. 40 tankers were completely inadaquate for moving the petroleum from the US, Venzualia, or the DEI.