On our trip in May of last year there were many places we didn't see any Mex's.
Some of the resentments, and they're legitimate, are more regional I think. You never hear of problems in NYC like you have in CA and it's loaded with illegal South Americans. Probably Mex's also.
It's like the Gov is damned if they do and damned if they don't take some serious action on all these illegals.
But unless they start to seriously fine or imprison those who hire them, this wont end. If there are those willing to hire them, they will find a way to get here.
Welfare and any other bennies they get should be stopped immediately. That too encourages people to come here illegally. OTOH our Gov should speed up the process of getting them here legally and have a quota. I can see how frustrating it can be for them to have to wait years to get documented.