".........wouldn't it be nice not to generalize when we post negative comments?"
miffed

Indeed it would. Putting aside perceptions, though, it may be more effective to simply state the facts. In your case, I think the facts speak for themselves; you consider yourself a qualified teacher and that's what should mean the most to you. If you continue to improve yourself as a teacher, the false perceptions of others are irrelevant.

Moreover, as Turnoi noted, there are many, many, Caucasians here who, shall we say, are somewhat less than qualified to be in the classroom.

But lets keep in mind that, though there are a lot of unqualified EFL teachers in China and, though some of them have agendas that have nothing to do with teaching, there are many who have found a way to improve themselves as well as their students. And, too, there are many who have not.

At any rate, sometimes, once the hornets nest has been stirred, it's best to walk away smiling.....or maybe pondering. Or both.