Korean
Well I had a friend who joined Korean few years ago. He said things very similar to yours. He too was failed for an absord reason.(Too petty even to mention). Like Dream Land said changing the instructor was a very very bad idea. But then again you did not know that. With almost all Koreans respect and the SIR business is required. High Raki is at its max. This is by nature. Another pal of mine who used to work over there gave it up after 2 years. He said no local talks to you in the flight deck. The locals will speak out the standard calls no nothing else. Infact I know an ex Captain from Korean who is a Korean himself gave me the inside picture. He is presently employed in the same company as I am.
So after all this has occured to many at Korean. Just put it a side and look else where. There are many oppertunities. Take it as an experience. Dont let this harm your flying career.
Look at the incidences that have occured over there in the past.
So what I would say is that this happend for your own good.