Still thinking about the “open borders” beliefs of much of the Left. While it is true that at one time there were no documents required for international travel — no passports, visas, etc. — we do not live in that world any longer. What proof is that older world of anything? We also used to torture cats for amusement and burn witches. Using the past as a guide will often only guide you into a crevasse.
The Left is correct that there does exist much inequity that needs to be addressed and that much (though not all, as they claim) of the refugee and migrant crisis is the fault of rich Western countries.
However, for much of the Left the IYI answer is to allow everyone to migrate from a poor country to a rich country. This both destroys over time the rich country and the poor country — I hope for obvious reasons or you might also be an IYI. This does not scale and simply cannot work unless you wish everyone (rather that some) to be immiserated and to also make life much worse for Western women.
It’s clear that for the Left, open borders is a religious belief, not a well-considered position but it’s still worth contemplating the idea intellectually as not all ecclesiastical ideas are by necessity bad. The conclusion is that it works fine for a religious belief but rationally and from a risk perspective open borders makes little sense. Attempting to address inequity and iniquity where it lives is a better answer; this will improve lives everywhere, rather than just a few lives for a little while so some Lefties can feel righteous.