If you didn't pick up these hints during school, you weren't taught to think outside the box. And there's nothing wrong with an empire. Think of it as more in terms of "sphere's of influence." China has a lot of power in South Asia, Russia still has its "bloc," there's been a constant struggle for power in the Middle East, Nigeria and Brazil also carry weight on their continents. The USA, to me, started this kind of empire like building in the early 19th century with the Monroe Doctrine as they set out to prevent European (mostly Britain, btw) was establishing imperial states in the Western Hemisphere. Britain was a trade partner but also an enemy at the time. Since we( the USA) kicked off the Industrial Revolution and the age of modern innovation we have been able and have aggressively sought to pursue opportunities that are beneficial to our now multi-national corporations.
Much of this country's global military expansion didn't occur until after both World Wars, when much of Europe was devastated. We rebuilt a lot of those countries infrastructure and more. And a lot felt like we saved them from certain Nazi occupation. It was welcomed at the time.