[nickik]

That is a very one sided view of things. Lots of assumptions that have been proven false over and over again. If you actually look into the economic research on this questions you will quickly see that its very hard to make a case against immigration. Anti-immigration economists have to make arguments such as "over a period of 30 years immigration reduced the real wage of people without a high-school degree 5-8%". And that's of course a terrible argument that does not hold up in comparison with the positive effects.

Essentially xenophobia is the only reason why people are against immigration.