Economics research on these questions shows that immigrants create their own labor demand and are generally competing with fellow immigrants for a different set of jobs than native born workers. It is why the wage effects are minimal to non-existent.
As for social services, these workers often are paying significantly more in taxes than what they get back in return. If anything they sustain the social services in an aging population.
David Leonhardt might be one of the loudest bullhorns for the dumbest reactionary stuff at the Times.