Most likely an extremist private school, teaching a (moreso than usual) perverted interpretation of Nazi doctrine.
This is just a complete guess of course, but its the only sense I can make of it. First of all I would not say that any form of Nazism would be mainstream there, certainly not in regular public schools. Second of all, I don't think Hitler's idea of a master race made any provisions for the Thai people. I'd go so far as to say that whatever is going on there is more closely related to communist doctrine, with Nazi overtones. I only say that because I think from an emotional level the concept of a master race is easy to get behind (as long as you are the master race of course) than communist tendancy that takes the focus away from indiviual acheivement/entitlement and places it into society as a whole.
Whatever the real story is here, I didn't see or hear anything approaching this in my time there a couple years back, I certainly wouldn't think this was typical at all. There are wackos everywhere, looking for any excuse to blame someone else for thier misfortunes, and they'll look anywhere for the tools to drum up support for their cause. Too bad ignorant, undereducated kids are the ones frequently tageted.