That's somewhat of a straw man argument that has been around for half a century.
Point of fact, most illegal aliens file taxes, utilizing an ITIN. And, ITIN holders are still eligible for the Child Tax Credit (CTC) and the Additional Child Tax Credit (ACTC).
There is a special form, that can only be utilized by those using ITIN, when filing .... Whereas, if one is working legally in the United States of America, all children claimed must have a SS#. For those ITIN filers, this is not requisite or mandatory. Simply naming the dependent minor and the city residence is sufficient.
So, there's Jose in Nuevo Laredo, Lupe in Juarez, Jorge in Monterrey, Juanita in ..... And the list goes on Point of fact, 2008 figures showed that the average ITIN claims nine children ... that's the AVERAGE.
Now, figure what the CTC and ACTC add up to, per child ... multiply that by nine ...
That's a lot of pesos, Juan .... FAR more than the minimal SS contributions made under their fraudulent use of Social Security numbers.
Of course, there's food assistance, housing assistance, medical assistance, cash stipends .. and the list goes on.
So, it surely as hell ain't following the money.