The apology issued to the Japaness people was because the it pissed off the Americans so much, and Japan suffered as a result. The Japanese were only sorry about it because of the negative consequences for Japan, otherwise it would have issued the policy to the US and the American people. 50 years later, and they still couldn't apologized to their victims, only to themselves.
If they had broken off diplomatic earlier, would Pearl Harbor attack have been as asuccessful? If Pear Harbor had been on a war time alert, would it have succeed? If the US fleet had been in a war time readiness alert, and the Japanese fleet detected long before it was in striking range , what would have happened? The success of the Pearl Harbor attack was like the result of those peace negotiations.