We had synthesized rubber, so we no longer needed the rubber plantations on the pacific side. What exactly were the Japanese keeping us from importing?
Likewise on the other side, what were the Germans stopping us from Importing? Were we getting food, or steel, or coal, or anything useful to a war effort from Europe? Or China?
It seems to me it was the British that needed the Supplies, and that we were the ones supplying them.
On the other side, the Japanese were attacking us because we were interfering with *THEIR* necessary trade. Once again necessary because Japan is also an Island(s).