No – that's incorrect; you aren't being objective. You aren't even identifying the problem – what you appear to be having difficulty with is "diction" rather than accent, quite a different thing. I have interviewed employed teachers from all over the world – one of the major factors in employing them is working out how they perform in a class. Any accent works, but if their diction is poor, the students won't learn. Of course there are many people teaching English in Thailand who really have no idea of the language they are teaching, like not knowing the difference between accent and diction - - minimum training – and don't understand how English varies and if or how that affects the teaching. If you are going to teach English, it's a good idea to know a bit about the language you are trying to get across – usually this is "international business English". You want to get over 4 aspects – speaking, reading, writing and listening. None of this is accent-dependent; in fact students are quite advanced before they can differentiate accents. If they have trouble listening to the teacher, it is really down to the person who employed them for not recognising this...and of course, teaching itself is a skill on its own. Like they say, "those who can do and those who can't teach,", but it overlooks the fact that a lot of those who do (speak English) can't teach.
