I think it’s both! USA is not single person dictatorship after all. It’s similar to British Empire in 19th century. Did they did things to protect their interests and increase their power? Yes, of course they did! But didn’t they do also positive things for whole humanity, like fighting against slavery at one point? Yes, they did that too at the same time!

And USA helped Britain to not lose WWII in exchange of them giving up their empire and USA becoming superpower.