This association comes from the fact that many of the alimentaciónes are owned and run by Asian immigrants. When I was speaking to one of my students in English, he was talking about these stores and translated them as "the Chinese stores." Spaniards also assume that anyone who appears to be of Asian descent is Chinese and will refer to them as a Chino, as my Filipino friend has discovered over and over. All of this comes across to me as insensitive and a bit racist, probably because I come from more diverse culture.
These practices would not be as accepted and unquestioned in America. Nowadays in the U.S., we talk a lot about political correctness and the importance of it. While I believe people in the United States definitely have a lot of room to grow and improve with regard to their own issues related to racism and insensitivity, it has been interesting to compare the States and Spain in these ways. After talking with my friends from the States who are of Asian descent, I hear how they struggle with some of these common experiences in Spain. However, I have not spoken much with Spaniards of Asian descent to see their perspective on all of this. I try to remind myself that just because something is not considered good or acceptable in the United States doesn't mean it can't be acceptable in other places and cultures. That being said, I personally refer to the convenience stores as alimentaciónes because of my personal opinions and perspective.
