Lack of education is a significant part of this. Military (as well as police and fire) are readily available routes out of poverty for many of the poor. Ditto many apprentice programs. Usually they need a high school diploma. Too few of those seeking a better life fail to stay in school.
Todays military is more technical and requires more skill than the old days of sitting in a foxhole. Remind kids to stay in school and get that diploma. Then others will help you train for job skills.