You're missing the point. Shintoism during the war was used by the Japanese government to whip people up into a fighting frenzy. In particular, it was used to exhort the kamikazi to do their deed. It may have been a peaceful religion before the war, but certainly after its misuse during the war it is not considered a religion of peace and most Japanese are ashamed of that chapter of their history. Shintoism in today's Japan is all but dead.
We sang The Battle Hymn of the Republic at the end of the Memorial Service in the National Cathedral on September 14, 2001, and I thought it was pretty cool.
Mine eyes have seen the glory
Of the coming of the Lord;
He is trampling out the vintage
Where the grapes of wrath are stored;
He hath loosed the fateful lightning
Of His terrible swift sword;
His truth is marching on.
Chorus:
Glory! Glory! Hallelujah!
Glory! Glory! Hallelujah!
Glory! Glory! Hallelujah!
His truth is marching on.
I have seen Him in the watchfires
Of a hundred circling camps
They have builded Him an altar
In the evening dews and damps;
I can read His righteous sentence
By the dim and flaring lamps;
His day is marching on.
Chorus
I have read a fiery gospel writ
In burnished rows of steel:
"As ye deal with My contemners,
So with you My grace shall deal":
Let the Hero born of woman
Crush the serpent with His heel,
Since God is marching on.
etc.