I don't think that our educational system should include songs which celebrate war. Is there any discussion why we teach children to sing about the attack on Pearl Harbor as if it was a divine commandment? We have our youngsters sing "Tora, Tora, Tora tziva lanu Moshe" - why would we encourage this?
1 Answer
Because that generation were evildoers, and despite this environment, their progeny would go on to become tremendous tzaddikim.
Precisely for this reason, at times of celebration/religious ceremonies (e.g. Shabbos, Yom Tov, Weddings, Bris etc.) we recite the brocho:
בָּרוּךְ אַתָּה ה', אֱלקינוּ מֶלֶךְ הָעוֹלָם בּוֹרֵא פְּרִי הַג'פן
Blessed are you Hashem, our G-d King of the world, who creates the fruit (i.e. later generations) of Japan.