That changed when President Barack Obama put in place the Deferred Action for Childhood Arrivals immigration policy in 2012. Under the program, undocumented immigrants who came to the country as children could apply for temporary deportation relief from the federal government and be allowed a work permit. But they still needed official documents to prove their identity to federal immigration authorities.
The Mexican government's foreign service jumped at the opportunity to help, asking its consular network to issue protective passports to its citizens in the United States to facilitate the DACA process.
How Mexican officials are giving IDs to some in US - Chicago Tribune
What IS wrong with you, Mexico? YOU need to take care of YOUR kind; NOT pass your citizens off on the US to care for.