What pragmatic argument? You just asked for evidence there's a limit. Anyhow, there's a plethora of studies that have been done on the economic impacts of mig

What pragmatic argument? You just asked for evidence there's a limit. Anyhow, there's a plethora of studies that have been done on the economic impacts of migration, expected outcomes to immigrants measuring different factors (wages, employment, and subjective measures of assimilation), and so on. It's basically an entire field in itself. What is the real 'limit'? The answer is when the negative societal effects become greater than the positive ones, and the host population decides to limit immigration. The rest of your post was a moral argument, which again, doesn't matter when the population has decided they're at the 'limit'.