Many of them may very well be American citizens of Mexican descent. Some of them are Filipinos or Japanese. but they have been out in the sun so long. they all look the same color as the Mexicans. anyway. Others are here on green cards. legitimately. and some may very well be illegal aliens. but you do not know. You round up the whole bunch. Whether they are illegal or not. you disrupt the operation of that farm. you scare them to death. and you cannot get the harvesting operation going again the next day. or the day after. because so many of the workers are scared to death to come back to work. including those who are citizens of the United States.
Identified stereotypes
People working in the sun all look the same color as Mexicans.