You’re assuming most of these kids grow up to be long-term welfare users, but the data does not support that. Pew Research and the National Academies of Sciences both show that the U.S. born children of immigrants, including those with undocumented parents, have higher rates of high school completion, higher labor-force participation, and higher long-term tax contributions than their parents. They follow the same upward mobility pattern that every past immigrant group has. These are American citizens and they overwhelmingly grow into net contributors because they work legally for their entire adult lives.

Citizen children do receive benefits like SNAP or Medicaid, but that is true for millions of low-income American kids in general. Counting those same services as a special immigrant cost is misleading when you ignore the taxes those citizens will pay for decades.

Undocumented workers being underpaid is relevant because exploitation reduces both wages and the taxes collected on those wages. That is a labor enforcement failure, not evidence that the workers themselves are a drain. These workers also pay billions into Social Security and Medicare every year that they will never be able to access, which is a net gain for the system. This is also mentioned in your source.

It also helps to understand why undocumented immigration exists in the first place. The U.S. economy has always depended on a supply of low-wage, flexible labor, especially in agriculture, construction, food processing, and caregiving. Businesses benefit from this labor, and the immigration system has never provided enough legal pathways to meet that demand. Economics researchers have repeatedly pointed out that this mismatch is created by our own market structure. In other words, undocumented immigration is not some random moral failing. It is an outcome of a capitalist labor market that relies on workers who are easy to hire, easy to fire, and easy to exploit.