Teaching jobs and the real meaning of "Native English speakers"

I've been doing some research on teaching in Vietnam. One of the common talking points is that you need to be a "Native English Speaker". Is that really just code for being "white"? Because I'm Asian, have lived in America since I was a kid and speak perfect English. However, I'm concerned that despite this, I wouldn't be seriously considered for a teaching position. Quite a few have said similar things even if it's not considered politically correct. But if this is true, then I don't want to invest the time nor money with getting TEFL or CELTA certification just to be disappointed.

What are your thoughts?