Sorry for such a slow response - and for being unclear in my comment . Respecting all parties, I attempted to point at the fact that they (the Japanese) appear to be, as you say "brutally honest" about innate human dishonesty, whereas we in the West tend to (dishonestly) externalize evil, e.g., as a personalized Satan, which I see as a plus point in their favor.
I agree with you that there is an awareness of evil in all cultures, due to it's presence in all societies. The Japanese appear to be honest in openly recognizing it as a human weakness. In contrast, saying that someone is possessed with an evil spirit, that can (hopefully) be 'driven out', implies that the evil spirit is seen as a separate entity. This perception may have some therapeutic value; I do however think it is more honest to recognize the perpetual subconscious presence of potentially evil motives that need to be kept suppressed in every one of us in order to perpetually behave in ways that benefit quality of life all round and thus contribute to one's one quality of life as well - which seems to be the Japanese philosophy as well.
I'm jealous of your first hand experience of that society and will certainly make work of studying what you have written about it, when time allows - Thanks for having done so!
RE: Top 4 Reasons for Leaving Japan (Notes from Under the Tatami Mats–87 … My Adventures in Japan)