US policies rely on and encourage immigration for more innovation. Why? Those immigrating have a better education and stronger motivation to succeed. The process of immigration stimulates the imagination about the value of being engaged. The American educational system is weak and stimulates less interest in the future, in science, language, and family solidarity.
The US middle class is right that conditions favor immigrants. Just look at the names of Silicon Valley's top management. Why does this happen? There are multiple causes but look at the incentives from the management trying to grow and innovate: immigrant engineers are better educated cheaper to hire and more robust, having been through hell by the reality of immigration and then integration into existing schools. having overcome a lot they are tougher and more motivated, urged to succeed by parents that arranged the immigration.