1. The basis of morality can be any number of things, to include religion of one persuasion or the other.
2. Morality is learned. If you have ever been a father or mother, you know, from observation, that children are amoral little wretches at best until they are taught better. More proof of this may be obtained by looking at some of our up-and-coming young "celebrities".
3. In a military career started in 1961 and ending in 1991, I never had a chaplain or another soldier attempt to actively proselytize me or anyone else. I did have soldiers who would openly discuss their beliefs, but only if asked.
4. In my experience, those soldiers who changed from one religious belief system to another were inspired by either the example of a fellow soldier or the example of a chaplain. Notice that I said, "by the example" and not "by the words".
An anecdote told concerning the campaign on Guadalcanal during WWII concerned a Protestant chaplain going to Major Lewis B. Puller and asking him to put out an order forbidding the Protestant Marines from converting to Catholicism. Major Puller, in his inimitable growl, said, "Chaplain, when I see you up on the front lines with my Marines as I see the Catholic chaplain, I might consider it." Nothing more was ever heard of that request.