I live in Southern California and the majority of legal Mexican immigrants, by an overwhelming margin, disapprove of illegal aliens first and foremost because the legal immigrants got their citizenship the hard way and do not approve of the illegals coming in and lowering the “bar”, as in taking all of the low paying jobs at a severe discount thus eliminating the available jobs for low skill legal immigrants.
Just my observation in San Diego, but depending upon where you live most likely matters most on the outcome of such a “poll”.
That's interesting. I live near Oxnard, birthplace of Cesar Chavez of United Farm Worker's fame. It's basically a Mexican town inside the U.S. and serves as a transit point for illegals to farm and other jobs here. There's a strong pro-illegal feeling locally but of course I haven't conducted a scientific "poll." I feel in my bones most have more loyalty to Mexico or "Aztlan" than to America. I hope your sense of things is the correct one.