One thing to note is that one can (and should be) a good, honest, moral person even if he is not a Christian. And being a person of high moral standards alone does not make one a Christian. A Christian specifically believes in Jesus Christ, acknowledges him as Lord, and takes his Christian walk seriously.
So, George may well have been the “wisest, bravest soldier.” But the answer to the final question is that many professing Christians (you might even introduce to them the term “Protestant”) do not interpret the New Testament like we do. They believe that although “killing people” (as in murder) is wrong, they also think that soldiers serving under a government must fight and kill when ordered to do so for a cause that the government says is right.
An Anabaptist Resource for Teaching and Learning
The Dock is conceived to serve schools in the spirit of Christopher Dock, the devoted teacher who authored a warmly practical teacher's manual in colonial America. Read more...