We need both : open borders and very small governments without a welfare State.
If you remove the bad incentives to move, you solve the migration problem.
But open borders are important too : walls keep people out but also keep people in. That's too much power to give to governments.
And as a human being, I do not recognize the authority of governments to prevent me from going where I wish to go on this earth, as long as I'm not trespassing on private property.