Oh yes they were stupid. They had superb submarines and torpedoes but did not use them in any meaningful way to interdict supplies flowing from the west coast to Australia, or from Britain east through the Indian Ocean to Australia.
Well, guess we will have to live with a permanent disagreement over this...
You’ll have the advantage over me since, at my age (89), the disagreement will not last more than 10-15 years...
OTOH, as those of us remaining who lived through WWII go to ground temperature, history revisionists can run free...