If you disagree with your instructor's explanations...you should be able to back up physically your opinion. It means you simply counter his/her technique.If your counter works - you are right and if you can counter all his techniques, well, you become instructor and he must learn from you
However, if he is able to do his technique successfully anyway, well, bow deeply, shut up and train harder.
As you see, it is so easy to solve your problem. Hope it helps.