I imagine that to Mexican "undocumented workers" they are like Cinderella and the U.S. companies employing them are like the evil step sisters taking advantage of their labor to get jobs done that they don't want to pay fair wages for.  U.S. immigration policy is the step mother saying "clean the toilets, harvest the broccoli, change the hotel sheets and maybe later on I'll let you go to the ball."
     When did these illegals (let's call them what they are and not confuse the issue with Orwellian doublespeak) start to believe they were entitled to jobs that should rightly be offered only to American citizens and those who enter the U.S. legally? The argument that "no one in the U.S. wants these jobs anyway so let the undocumented workers to them" is fallacious.  Each U.S. citizen or legal resident isn't going to attain identical skill sets.  There is a section of the population for whom these "service sector" jobs match their skills. There will always be a portion of the population in transition and that covers anything from being in the process of learning adequate language skills to establishing roots after moving to a new area.  These "unwanted" jobs fill the temporary yet very real job needs for these populations.
     That it's illegals that are being given these opportunities and not America's own is short-sited policy.