You're certainly correct in pointing out the numerous examples of hypocrisy in the propaganda and poetical rhetoric of this government versus the actual actions of the nation. This nation was founded on genocide and slavery and continues to perpetuate these horrors both domestically and within a global context. While plantation chattel slavery was technically abolished by the enactment of the Thirteenth Amendment, the amendment also specifically states that slavery is abolished except in cases of incarceration. As such, mass incarceration has replaced slavery.
Presently, the United States incarcerates more people per population than any other country in the world. However, due to the rhetoric of "law and order" and "justice", we are taught to accept the caging of people behind bars as an acceptable course of action. There are currently people languishing for years in prison who have yet to even go to trial, and people are held behind bars because they are too poor to afford the bail amount that the state has set over their heads. These folks have been stripped of their freedom, and any attempt to escape will be met with violence, punishment via additional sentence length, or even death. What is this but slavery? Segregation is, as you pointed out, absolutely still an active part of this country. Public schools attended by mostly working-class students of color are for the most part disproportionately underfunded and heavily policed. Students are often subjected to racism by condescending white teachers, violence and brutality by police, and even consistent encouragement from "guidance counselors" to drop out of school.
As you also pointed out, children are being kidnapped from their families on the border, and people who have come here to seek refuge are being incarcerated and punished. The vast majority of these people being incarcerated on the border that was created by the United States are indigenous to this continent and/or descended of African people who were forcibly brought to this country via enslavement. Many of these indigenous and afro-indigenous migrants are being forced to make the deadly journey to this country precisely because of US economic and military polices that have destabilized their home countries for decades upon decades. This border was created through state violence, and the border is being violently enforced against people who have more ancestral connection to this land than the many of the people guarding this state-created border.
The noble words of acceptance, liberty, "pursuit of happiness" and the like found in the Constitution, in the Declaration of Independence, and on the Statue of Liberty are nothing more than political rhetoric aimed to convince people that they are living in freedom while they are, in reality, living under authoritarianism. Most of the men who penned those documents owned enslaved human beings and participated and/or encouraged the genocide and forced displacement of the indigenous peoples of this land.
You are correct and wise in seeing the actual workings of this country. While this country is certainly notorious for human rights abuses, incarceration rates, and racism, it is not unique in its oppression, as governments exist through the control and oppression of its subjects. Without governments or centralized power, there would be no prisons, no borders, and no standing armies or police that exist to bolster the power of those in the ruling class.