The only problem I have with immigration is the illegal kind. Illegal downloading is fine, it just gives you a test of software you may or may not find useful enough to buy so the developers have the resources to improve the software, but illegal immigration can cause economic problems for individuals. For instance, one of my friends was working as a waiter part-time (about 10-15 hours a week). One week, they suddenly find that the record shows that they worked 60 hours that week, although they did nothing different from their usual schedule. The cause: an illegal immigrant was working under my friend's name, taking the money for their time, and letting Uncle Sam dip his hand into the 10-15 hour pay by making my friend pay the income tax for the extra 45-50 hours worked.
Oh, and FenriSulfr, the blacks helped build America through slave labor. Get off your high horse and take a walk-you may learn something from your history class.