I think a big part of the reason this was a theme in TNG was because it was supposed to get people in the '90's to reflect on whether the USA was actually the hero of the story that our history, politicians, and media tells us we are, or whether the idea that we're "more civilized" than other countries was a lie we spoon-fed ourselves.

I mean, it's an idea that sat with me most of my whole life. We are not the heroes of our stories, and a lot of the stories we tell ourselves are kind of a self-deception propaganda to justify why we have a higher quality of life at the expense of the rest of the world.

USA was at the time a country that promoted itself as one of the least violent and most civilized nations in the world. The US government was hiding behind "We don't cut criminals heads and hands off" as though we don't use psychological torture much more often on our own populace.

They can't really hide behind "our police aren't violent" so much anymore, because it was clearly always a lie.