I liked the movie but it was part of the widespread media painting of vets as psychos, in TV dramas, movies, and cop shows, the sniper/killer/Psycho was almost always a Vietnam vet.
Serving America in the military made men mentally ill was the theme. I do think though that as nuts and disturbed as Rambo was, Stallone did such a great job in making an action movie that Rambo ended up coming off to the public as a Vietnam vet hero.
Rambo actually helped the Vietnam vet image as bizarre as it can seem, and it started the public thinking of them as skilled combat guys, heroes (well, it was a slow start toward that). In the end it fit the 1980s very well.
When I watched it growing up, I didn’t think he was crazy and I was on his side.
The cops were scumbags.