After reading the link you posted I can say that that the advertisement does not prove anything. The school wants degree holders and TEFL/TEFL certified teachers if possible. And many schools in China say they want teachers with experience teaching in China. So what? Does that mean Shane is a good school?

No, he didn't say as you said "if possible".He said "must have". That's you surmising again. And what you say doesn't PROVE anything either, as can be seen from what you have just said!
I haven't a clue whether Shane in Dalian is a good school or not. Actually, I don't wish to teach at that kind of school. Good school or bad school, I don't give a damn!
The heading of this thread has emanated from my wish to know the reason why Shane asked for only native English speakers to apply, that's all. Maybe it's not as he has said!
I happened to mention that I thought restricting Z visas to native English speakers would be a good thing. But it wasn't the purpose of my post to start a quarrel about that. However, I'm entitled to my view re that, as you are too, of course!