In the small city where I grew up I got to know the owners of three local Chinese restaurants of the type Zimmerman insulted. They were new immigrants to Canada, living in an all-white environment that in that era was hardly tolerant or welcoming. They were among the hardest working, most decent people I've met. They made a better life for their children, many of whom went on to higher education, entered professions, while at least one or two stayed to run the restaurant.
So screw Zimmerman for insulting some of the best people I've known. I'd have fired him too.