White-skinned native English-speaking teachers are definitely preferred in Thailand and all of Asia. That's good news if you happen to be white as it effectively eliminates a good portion of your job competition. With few exceptions there are very few non-white English teachers in Thailand. My previous school even preferred barely understandable non-native English speaking white South Africans and Russians over non-white native English-speaking teachers from America and the UK.
Thais clearly prioritize presentation or looks over substance or quality when it comes to English teachers. They perceive white skin and Caucasian features as more attractive and presentable across Thai society. The longer I live here, the more I tend to agree, and as a white westerner as it works to my advantage. But it doesn't mean it's impossible to find a job as a teacher if you're a non-white, however you'll need to be very persistent, patient and flexible in what's offered.
There is no wrong or right about it. Thais get to decide what works or doesn't work for them. It's their world and they like it that way.