I'm not Japanese, so i don't feel comfortable speaking for Japanese customs or traditions or even their culture because frankly I don't understand it. Culture and tradition itself is usually steeped in history and in the west we assume Japanese people still adhere to strong culture and tradition and even as an outsider it's clear to see that Japan still holds on to it's customs of honor and dignity, is suicide still considered honorable in Japan? that's something to ask someone who has more of an everyday connection to the culture. Also not everyone in Japan is catholic or religious so it being a religious moral is moot.

you could argue if it was a social thing tied to Bushido, but it would be something unrelated to religion. Bushido is probably why suicide seems to be a problem for men in Japanese culture. I would say that culturally there is a pressure to succeed that doesn't exist in other cultures and that could have come to being from the ideals of Bushido, and honorable suicide or honor code in general. I think that could be something looked at as exclusive to Japanese culture.