Conspiracy Theories about the Japanese attack on Pearl Harbor on December 7, 1941

Every year we commemorate this day that will lives in infamy! Every year several conspiracy theories are warmed up again and are regurgitated!

Most of these conspiracy theories are garbage and they only superficially sound convincing or plausible. They often claim to tell you the truth! Purveyors of such conspiracy theories have often ulterior motives like implying that the U.S. was imperialist and a war criminal as well.

However, as usual history is most of the times much more complicated than what talking heads like to select for their presentation. See e.g. Events leading to the attack on Pearl Harbor. Japan in the first half of the 20th century was a military dictatorship invading and attacking various countries etc. to build their empire.

Here are two examples:

1. The November 1941 U.S. oil embargo against Japan provoked the attack (see e.g. here). Picking one singular measure out of a history of many events and measures by various parties involved to explain a course of historical events is a sure sign of demagoguery 
2. The U.S. had advance intelligence information of an imminent attack on Pearl Harbor, but did not warn the military command stationed in Pearl Harbor. How many lives were saved by keeping it secret from the Japanese that the U.S. was able to crack/decipher their diplomatic and some of their military codes?