Is that the Breitbart conclusion....  seems the Commission report  said...

"Among its findings, the Commission notes that the illegal workers are estimated to account for as much as one-third of total immigrants in the United States, and that illegal immigration has
tended to increase the supply of low-skilled, low-wage labor available. The Commission found
also that about six in 10 adult black males have a high school diploma or less, and are
disproportionately employed in the low-skilled labor market in likely competition with
immigrants. Evidence for negative effects of such competition ranged from modest to
significant, according to the experts who testified, but even those experts who viewed the effects as modest overall found significant effects in occupations such as meatpacking and construction."

In Kirsanow Breitbart darling on the topic of immigration, merged 3 studies into his personal summary.  This is from the Briefing Report Issued by the US Civil Rights Commission.