Thanks for that thoughtful response Richard. In particular I would tend to agree with this:

"those who volunteer to fight must surely be mostly those for whom fighting rather than the triumph of good over evil is a virtue, because they know when they volunteer that they do not have the choice of whether they serve good or evil "

As a musical aside, I just realised that one of the folk songs I sing vividly describes some of the issues touched on here. Arranged by Andy Irvine and based on a Romanian folk song collected by Bartok at the turn of the century, to me it feels as keenly pertinent today as ever:

Blood and Gold