Immigration and outsourcing are two different things.
As for immigration, the USCIS checks on whether immigrants are qualified, have sufficient education, and do not displace US workers for every visa longer than 3 months that they approve. If you think people are working as immigrants in the US while underpayed or displacing qualified US workers for the job in their local market, let USCIS know. They don't like fraud.
Curtailing US immigration will only make outsourcing of US jobs to other countried go faster, as departments that cannot work effectively due to lack of personnel are the easiest to make a business case for displacing to a low-wage country.