They may be ready to meet Allah on a small scale, but everyone wants to see their genes continue one way or another, and as crazy and maniacal as they are, even those looney toons aren't that stupid.
Are you absolutely certain?
If it worked the way you think WW II would have been over a good 6 months before it was. Also Japan would have never start a war as many of their best military minds knew that they couldn’t win we it started. Seems to me they had plenty of people that were willing to die, if they hadn’t we wouldn’t have lost so many boys taking Islands. You do remember that less than 10% of Japanese soldiers surrended. Also it wouldn’t have taken two bombs to end it. You do know that Japan only surrended because of Hirohito and even then the surrender only happen because a handful of Japanese Officers stop a coup and the arrest of the Hirohito?