Geez, so the break off diplomatic relations five minutes before the attack? Somehow that makes it ok? No, I don't think so.
The point is the Japanese government was lying. Note that its attack fleet had to leave Japan a week before (it's a big ocean to cross) under radio silence.
I suppose we could buy their argument that the Bataan death march was due to a shortage of transport. I don't. I suppose we could believe that the 1930s bombing and rapes of civilians in China was normal warfare. I don't.
The Empire of Japan had a run up a long record of atrocities by 1945. It does not make sense to suggest to give them the benefit of doubt regarding their cease fire proposals.
It should also be noted that the Japanese military command had a very selective view of "honor". They had no problem teaching their troops to never surrender and to die for the emperor. But when it came to saving their own necks, it was another story. They refused any serious attempt at surrender because they knew of their guilt in war trials.