Not who you were replying to, but freedom of movement is a fundamental human right.
You can say it's a right, but I'm not sure there's any wealthy nation that believes that any random human should be allowed to travel wherever they please without paperwork to prove they belong and/or are safe.
I'm not really a fan of real ID, but I also think that the US should has a national ID and the US has the right to deny free travel to those it didn't invite in anyway.
Look, humans are by our very nature nomadic, we traditionally used to have a “seasonal round” where we lived in multiple places in a given year to have more access to better food/water sources etc. Being able to travel where you like is a fundamental part of being human, borders restricting that are what’s weird, not the other way around. Restrictions on travel are a relatively new phenomenon. The difference is it was just physically harder to get places 1000 years ago, and that formed its own sort of barrier.
Someone else said that you used to not need ID to even fly before TWA800, I don’t know if that’s true, but I do know that you could walk up to the gate when I was a kid. And why should you need an ID? Tracking every movement of every person doesn’t grant any sort of security to anyone.