There is a TON of anti-immigrant propaganda. Whenever the economy is shit -- which it often is now, because of the massive disparity between rich and poor -- immigration is an easy target.
It's easy to say things like market rates for labor are lowered due to an influx of immigrant labor, or that immigrants are taking jobs. There is a good case to be made that things like the H1-B program do artificially lower wages and do mean that there are fewer jobs for citizens -- but the spin is always against the immigrants and never against the companies exploiting them.