I don't think you realise that much of the world was under de facto dictatorships (eg. absolute monarchies) and it wasn't like people in the years before were living in democracies that then got taken away.
The US doesn't have a higher moral ground to stand on vis a vis many other countries in the world.
More recently, Sadam and Noriega until America turned on them.
Or currently, the Kingdom of Saudia Arabia, Egypt, and many others.
US allies in the entire middle east are literally all dictators or worse than dictators. For example, Saudi Arabia is an absolute monarchy, you just need 6 years education in school to understand that is worse than dictators when religion is also heavily involved at the same time.
if you want a good path to true improvement in civil rights (not a useless piece of paper or declaration) just track the wealth of a country. Wealthy countries that didn't rely on natural resources to get wealthy tend to treat their citizens better because, well, they make up the fcking economy.
most western countries had a shortcut to that via colonialism and slavery. It's very rich to then point at countries that don't have that cushion and talk about being morally superior.
Democracy is a morally superior system of government, because it's fundamentally premised on a moral idea; that governments "derive their just powers from the consent of the governed". Dictatorships and aristocracies can make no such claim.