HOUSTON — Immigrants and advocates are urging Democrats and President Biden to quickly act on legislation to protect young immigrants after a federal judge in Texas on Friday ruled illegal an Obama-era program that prevents the deportation of thousands of them brought into the U.S. as children. Plaintiffs have vowed to appeal the decision by U.S. District Judge Andrew S. Hanen, who declared the Deferred Action for Childhood Arrivals, or DACA, program illegal, barring the government from approving any new applications but leaving the program intact for existing recipients. Calling the ruling a “blaring siren” for Democrats, United We Dream Executive Director Greisa Martinez Rosas said they would be solely to blame if legislative reform doesn’t happen.