Limiting immigration is limiting economic growth. The time when the country grew the fastest and most dramatically was also a time when shiploads of people were just showing up.
Every time you see someone saying "we need regulation for capitalism to work" these are their victims. Democrats and Republicans both have a history of denying people human rights, and the right to employ whomever I want-- without regard to where they were born-- in my business is a right that they are denying. It also denies the employee the right to work for whomever would like to hire them.
Government doesn't know best. This is why socialism has never worked.
So, if you're lamenting the way these people have been treated, look to your own voting history.