During a 1967 strike in the Central Valley, for example, Chavez and the UFW demonstrated outside the office of the U.S. Immigration and Naturalization Service (INS) in Bakersfield, criticizing the agency for not arresting what they called “illegal aliens” and “green carders” (who were prohibited by an injunction from the U.S. Secretary of Labor from working in struck fields).
This soon led to the arrests by the INS of hundreds of undocumented agricultural workers.
In 1974-75, the union engaged in what it called the “Campaign Against Illegals.” The campaign’s most famous component was what the union named, in reference to “wetbacks,” the “wet line”: a vigilante group of a few hundred individuals wearing “UFW Border Patrol” armbands who policed a ten-mile or so stretch of the Arizona-Mexico boundary over a three-month period—with the effective approval of local and federal officials—--arresting and often roughing up those they encountered.
Chavez was simply reproducing an old strategy, opposing the use of migrant workers to undercut native-born ones, which he had utilized in protesting the Bracero Program beginning in 1959.
Historically, California labor relations featured --for well over a century --- the pathetic practice of one group of poor men desperately under-bidding another group of poor men to get the poorest-paid jobs in America. Chinese, Armenians, Filipinos, Mexicans, Central Americans, wave after wave of immigrants and "Okies" and "Arkies," too, arriving on the scene and dropping the wage scale over and over again.
It's the bane of agricultural workers: the constant competition from other desperate men willing to work for less.
Chavez saw this. His present-day admirers do not.