Illegal immigrants and legal aliens are not the same. There is a constant attempt to blend the two together into one "problem." Every high school graduate who enters the workforce is classified as "unskilled labor."
The "burden" of older unskilled labor comes from the home-grown variety, not illegal immigrants. There are far more American unskilled who will be getting Social Security, welfare and other support transfered from younger taxpayers. Illegal immigrants can't collect Social Security. Most paid into the Social Security and tax system via withholding using false SS numbers, but they'll never collect. The money is in a huge barrel of unaccountable cash that helps support the people who paid in legally.
If you want to howl against illegal immigration, I'll howl with you, but the politicans and pundits need to stop their hypocrisy of extracting the benefits of cheap, illegal labor with a wink while spouting off like a bunch of xenophobic rednecks.