https://cis.org/Report/Welfare-Use-Immigrant-and-Native-Households
Not only do the facts back this up, but stop and think about just how crappy the job market actually is in the US. Tens of millions of Americans can't even find work and tens of millions of American's can't even find more than a part time job.
https://www.cnbc.com/2016/12/02/95-million-american-workers-not-in-us-labor-force.html