@sterileprom "What's the fundamental benefit of transnational freedom of movement?"
@DuBarryPie "Why does free movement matter?"
The ideal of free movement can be aligned according to the polemic of "no entry" versus "no way out".
THE "NO ENTRY" POLE
The belief in "no entry", across a society, means limiting both immigration and citizen mobility. It means closed borders and, depending how extreme the "no entry" ideal is imposed, extends to government regulating and restricting movement of those people bound within national boundaries.
Closed borders aims to ringfence home territory. It gives authorities power over immigration affecting labour supply and, once regulating movement inside national borders, allows flexible region by region regulation, and opens potential opportunities - if desired - to impose homegrown-foreign apartheid.
Restrictions on free movement extended to home nationals provides legal ways to keep criminals, disrupting influences and insurgents where they can be tracked and neutralised.
As far as "no entry" advocates are concerned, the inevitable loss of personal liberty - which is felt primarily by non-comformists - is a small price to pay for all the government gains in extra capabilities to keep its loyal citizens safe.
THE "NO WAY OUT" POLE
Diametrically opposed to the "no entry" ideal are those for whom restrictions on the movement of individuals, including immigration and emigration and traversal of national borders, equates to a de facto "no way out" that's tantamount to imprisonment.
At its heart, it's simple. Freedom of movement means - for millions of people - freedom from the tyranny of national myth being twisted, in service of entrenched power, to create inescapable forces able to bind citizens in place, in debt, in check, indentured, without hope of parole.