My email has been running to about 90% against immigration, illegal or otherwise. From pleas to boycott Cinco de Mayo, which is, ironically, only celebrated in the American southwest to restatements of Mexico's restrictive immigration policies, it seems that most Americans have forgotten where their forebears came from.
As Cafe Hayek notes, the biggest complaint is that illegals are getting a free ride on the tax-paid government services bus, and that just isn't right.
The goods and services that people complain immigrants cause to be overused are either government-supplied goods and services (for example, government schools) or goods and services that are heavily subsidized by government (for example, medical care). No one complains that immigrants are over-using supermarkets, movie theaters, auto dealerships, or clothing stores. That is, private enterprise seems quite able to 'absorb' immigrants and prevent overcrowding and free-riding. Problems arise almost exclusively with goods and services supplied or subsidized by government.
The root problem is not immigration; it is government provision and subsidization of goods and services that should be supplied by the market. (emphasis mine)
I'll be brief, immigrants should not receive tax-paid, government provided benefits. Neither should you. That'll stir up a firestorm of email. You wanna get granny off the cat food? Move her into your house and fix her a bowl of Rice Krispies.