“It’s a fine distinction, but the implication is clear that the likelihood is very high that when one encounters an undocumented Mexican in the US (as opposed to Mexicans in Mexico), one is encountering a criminal, drug dealer or rapist.”
That is purely a reflection of your own biases. You are simply making an assumption. Obviously the people who are crossing the Rio Grande are not Mexico’s best and brightest. They are mostly not bad people, however they are far more likely to have, say… an elementary school level of education, or be illiterate. Educated professionals are not walking across the desert in order to get into the US. It is also obvious that someone who cannot legally interact with the economy or society is far more likely to engage in criminal behavior, if only because of necessity. You are fulfilling an ideological narrative, when you should be thinking with an open mind and displaying a little more intellectual charity.