Warning - this is a bit of a rant:
Over on the LA board, someone was complaining that all of the kitchen staff at some Indian restaurant was Hispanic. Somehow this distracted from his or her dining experience. And in the past, some people have complained about Mexican workers making dumplings at a Chinese restaurant.
Why does this matter? Does the person cooking the food infuse some special flavor or soul into a dish because of his ethnicity? As Anthony Bourdain has said in one of his books, more than half of the restaurant cooks are Mexican and some of them do a great job. Some of these guys are working even at really high end places.
The restaurant business is about the mass production of food (unless you're talking about a handful of restaurants like Masa or Urasawa). Whoever is creating your dish, whether fancy or not, is just trying to get that thing out as fast as possible without sacrificing quality and juggling a whole bunch of other dishes too. Nothing romantic going on here.
As long as the workers are being properly supervised and directed, it shouldn't matter whether your chef is Mexican or not. I will allow, however, there is probably some correlation between quality and the ethnicity of the ownership/management. For example, a Chinese-owned/supervised Chinese restaurant will probably be better than an Italian-owned Chinese restaurant.