How does amnesty help the average American?

First let me state that I want to end illegal immigration.  I also want to improve our legal immigration process.  We are a nation built upon immigrants, we need legal immigrants to keep our lifeblood flowing and keep our nation energized.  I am not against immigration, only illegal immigration.

Currently in Congress there is much work being done on a "comprehensive" immigration reform bill.  One of the core pieces of the bill is to provide a "path to citizenship" for anywhere from 11 million to 20 million illegal immigrants, which is a defacto amnesty. 

How does that help the average American?

We currently have more people out of the workforce since WWII.  Whole sectors of our economy are depressed and the number of jobs available are low.  Amnesty brings in more lower skilled, lower wage people into the US, and these people come here for two reasons.  The first reason is for a job.  So with our unemployment problem we will have more lower skilled workers competing in the workforce for a reduced number of jobs.  That drives employee wages lower, which is not good for the American worker.  How is that good for the average American worker?

The second reason these people break the law to come here is to get entitlements:  food stamps, welfare, Social Security, etc.  As a lower wage worker, you generally take more out of the entitlement system than you put in.  It's generally only those eeevil 1%'ers who pay more in than they take out.  Heck, we've been making payments to illegal immigrants for years already.  If we add up to 20 million people into entitlement system, it will bankrupt those systems even quicker than they currently are being bankrupted.  Estimates are that this bill will cost $11 trillion to implement.  Spending the money to cover these new additions would reduce what is available for the average American.  It would force the government to print more money to cover the costs, which reduces the value of the dollar in everyone's wallet.  It would force more of those eeevil 1%'ers to pay more in taxes to cover the costs, which reduces the funds they have available to create and grow businesses, or do other things to keep the economy moving.  That prevents new jobs from being created and reducing the unemployment problem.  How does this help the average American? 

Please note that I am not pushing an isolationist policy or a nationalistic one, as I want to increase and improve the legal immigration process.  I just don't see how this helps the average American.  Can anyone explain that?