2) When libertarians talk about any given issue, they do so within the libertarian context: the inviolability of private property. The inviolability of private property requires that no involuntary transfers occur. This tenet of in turn requires the absence of redistributive programs that allow immigrants to transfer weath by moving into a geography and obtaining redistribution (theft). Theft which therefore is used to fund the growth of the bureaucratic (parasitic) governmnet. This argument is that OPEN immigration is incompatible with the welfare state.
The alternative solutions are that a) people pay their way in, or b) they borrow and pay back their way in c) or that they are ‘sponsored’ by someone who is financially responsible for their productivity or loss (as was common in history). Further that they conform to norms that are expressions of property rights. Any one of these solutions makes immigration possible without violating property rights. Open immigration under redistribution doesn’t. I think this argument is pretty hard to refute.