It doesn't bother me at all to hear some Lao people say that they are "Laos," because when we refer to speaking it, we tend to say, do you speak "Laos?" So, I can understand why some people would think that saying they are Laos is correct. So really, I don't see the big deal to it. I do, however get annoyed when a 100% Lao person would claim that they are half Thai or Thai, just to hide the fact that they are Lao. That just tells me that the person is ashamed of being Lao; that is just too damn ridiculous.
For me, I love my ethnicity and my people, and I am not ashamed to say that I love Thai music and I definitely love Thai Lakorns. Loving Lao doesn't mean you can't love Thais and their medias and culture as well, but you don't have to forget yourself and lie about something you're not.