Illegal immigrants dont keep middle class wages down you dummy. They work at jobs middle class people wouldnt accept like picking fruit and cleaning toilets in hotels.
Why do you suppose Americans won't do those jobs? Perhaps it's because they don't pay enough. The reason they don't pay enough because eventually some foreigner will come along and take the job.
If you think foreigners only pick fruit and wash toilets, then you have another thing coming. They are in nearly every field of work in the USA. Trust me, I'm a truck driver, and they are flooding our industry. They are on the highway driving right next to your family mini-van in a 75,000 lbs truck and can't read a Fn word of English.