Graduating high school is a huge accomplishment that shouldn't be taken lightly. Some may not consider it to be as big as earning a degree or diploma from a post-secondary institution. But you wouldn't have gotten to that point if you hadn't graduated from high school first. High school was the stepping stone; a kicking-off point to allow you to move on to even bigger accomplishments.
High school is the first big graduation of your life, and for some it's the only one. However, for two war veterans, it's a ceremony they never got to experience in the first place because their country needed them instead.