I tend to look at an abrasive instructor as a test of my mettle as a martial artist. I guess that if he is teaching good stuff, with some attitude one should see it as an opportunity to build charactor. This easy for me to say as a person on the outside looking in. I just think that life is full of tests that while being hard, they make us stronger in the long run.
I guess my point is that abrasive or not this 7th dan is probably great at kata.
good luck choonbee,