I was a teenager, but I wasn’t so stupid that I didn’t analyze lyrics to songs people around me were playing and singing.
I hated the song then, and hate it now.
The song says a veteran can't get a good job because he spent his early adult years fighting a pointless war. So the only job he can do is the refinery near the prison. His brother is MIA in Vietnam (suggesting we didn't do enough to bring home MIA's).
I was about 15. I caught on immediately that it was an anti-American song. Never understood why the masses treated it as patriotic.