I wanted to add, that yes, as others have said, sometimes it is because their names are hard for Western people to pronounce. As well as people’s tendency to fear what is not familiar. Both of these reasons are why the people I’ve met who have done this did it.
If you go back in history, Asians immigrating from various countries to Hawaii to work the plantation fields would name their children with English names because white people were the dominant race and the other races were considered “second class”. Also, after WWII (think: Japanese internment camps), English names helped cement the place of innocent children of immigrants within Western culture. It is very common amongst Asian children born into Western culture to have an English first name and an ethnic middle name(s).