How is the argument much different than any current arguments? You can already get significant benefits from the state as a citizen (in European countries, at least).
The difference is magnitude, the benefits that European countries provide has made them a very attractive destination for immigration, so it stands to reason that something like UBI would make them even more so. No matter which side of that debate you're on theres a point where the math breaks down and some difficult choices need to be made, either you provide these generous benefits to your citizens or you have a generous immigration policy, but both of them together may prove unsustainable
Which is why unchecked immigration is already a problem. Increasing the benefits without dealing with unchecked immigration is going to make things worse.
