Um, it's a little deeper than that.
Maybe Los Mestizos simply want the freebies, but the Beeg Men they look up to want a little bit more.
They would like to rule us.
The number of Mexican officeholders in the state of California in 1970 could be counted on one hand. When you have less than 4% of the population, that's what happens.
But when you have 40 - 50% of the population, or more, well...that's how you get real power over the gringos, and are able to simply vote to take what they have.
And all you have to do is pull in as many of your simple minded shambling masses that you can, and somehow get them to be able to vote.
They aren't immigrants. They're invaders, and the commanders of the occupying army are standing around in plain sight, drooling at the thought of the Reconquest that they are effecting as we watch. And as our "government" acquiesces.