I can't speak for Clemenza but I have a feeling he is refering to the rather ignorant people who many of us had in our peer circle who plain did not LIKE Mexicans,calling them spics and wetbacks.
This was WAY before the illegal invasion.The debate on this issue should never be racialized but one needs to be honest and realstic and admit that many American whites-and many Mexicans here AND in Mexico-are trying to stir up the racial doo doo.
I don't like Mexicans because they are invading the United States. Mexicans are racist. Go take a look at their caste system with the white oligarchy on top of everyone. Ruling the brown Mexicans they encourage to invade the united States.