It's not over the last 30 years. That term was used as a propaganda tool as far back as WWII. In the countries that were invaded by Germany during WWII, those troops were known as German troops. Most of them weren't even Nazi party members. They were all labeled as Nazis in American porpedagna because America wanted to keep their sizeable German population on their side so an alternate label made sense. No special term was used for the Italians or Japanese, they were just called what they were, even though there were also very specific regimes running those factions at the time.

Since then, the Nazi term has taken up a meaning of its own to the point that is basically a generic insult you might throw at some one, devoid of any meaning.