While i think it is wrong to place value on someone based on their citizenship like most people do, i also think that the example of Brad Zazueta shows the ways in which targeting a group of people can catch unintended victims up in it. Zazueta was adopted at 11 weeks old after he arrived from Mexico into the hands of his adoptive parents.
During a traffic stop, he said he was from Mexico, despite having a California Birth Certificate (gee, he wasn't carrying his birth certificate with him? doesn't everyone do that?). There are apparently errors in his adoption paperwork, which means he's been sitting in detention for several months.
Clearly this incident, and people's attitudes as exemplified in many of the comments to the article, implies that what happened to Brad was okay because he actually is from Mexico. What happened to "i don't have a problem with immigration, just 'illegal' immigration"?
More info here.