Earlier quoted context omitted.
Freedom of movement is tenuous, and one of the greater paradoxes of the modern "libertarian" movement. The freedom isn't even universally supported on the left -- democratic socialist countries rely on high taxes and low economic inequality to maintain their systems, which, the reasoning goes, is unsustainable in the face of an unrestricted influx of economic refugees.
Having been born in East Germany I can assure you that the "Left" is not a proponent of free movement and that they will gladly attempt to shoot you for trying to escape from socialist paradise. Calling US Democrats "socialist" for wanting things like universal free health care makes me cringe in light of that.
Political discussions in the U.S. using the word "socialism" are basically meaningless, because people use that word to mean several completely different things:
1. Socialism as practiced in eastern Europe during the Cold War - basically the state is a prison, no one is allowed to leave, people who attempt to leave are shot and left to die, everyone is under surveillance, and dissent is punished very harshly. These governments were proud to call themselves socialist. In East Germany, they referred to themselves as "Socialism as it exists in reality" ("real existierender Sozialimus.") These are not governments that someone is now choosing to call socialist to give socialism a bad name.
2. Socialism as practiced in Europe these days, with a focus on Scandinavia. Somewhat higher taxes, reasonable universal health care, generally people are not left to starve in the street. I'm not sure if it makes sense to call this "socialism." I guess it's social-something.
3. Socialism as a scarecrow in American politics: Anything I don't like is Socialism. Any policy where the government provides benefits is Socialism. Any healthcare system where illness doesn't lead to bankruptcy is Socialism.
As a result, people talk past each other, and discussions tend to become nonsensical. Anyone who wants to have an informed opinion on socialism should just take a look at what happened in East Germany and the rest of eastern Europe from 1945-1990.