This ‘right’ only seems to exist for third world people coming to first world western countries. Try being an American and working in Europe - it’s a pain in the ass. Getting residence and work permits is easier if you have no skills and come from a hellhole. Reverse is also true

It really is at root a Marxist thing. Western countries must pay for their success by allowing hordes of people from primitive places exploit their countries. But Western countries make it hard for their peers to live and work in their societies.