Show me a company with a staff of monolingual English speakers, and I'll show you a company that only does local business.
And in certain parts of the country, those that do local business do it in Spanish. I lived in southern New Mexico and El Paso for years. The best places to eat were often the little "hole in the wall" Mexican restaurants where you placed your order in Spanish.
Nowadays, I work for a tech company based in San Francisco, and the level of diversity would absolutely terrify some of the people in the lily-white town where I grew up. Of course there's plenty of Asian Americans (with names like Tan, Lau, Nguyen, Chu, etc.), most of the managers in my department are women, and when I went through the interview process for my upcoming job, only one of the people I talked to was a white, straight male.
The "Make America Great Again" crowd doesn't want that. "Wait...your boss is a woman? And she's
black?" Yes. She's awesome. And a few months from now my boss will be a black immigrant. To my mind, this is what makes America great. Not Lumpy's dream of sending migrants who show up on these shores into camps where they can work for half as much as everyone else, but welcoming people who may not have names like "Smith" or "Jones" but have worth that can enrich our society.