Sachin has never in his 17 years of cricketing career come before the media and shown any frustration like this. Chappel's behaviour might have really affected him and he has done the right thing by coming before the media expressing his feeling to save the country's cricketing future.
He might have gone before the BCCI before telling his thought but might have gone to deaf ears. This might be the reason that he came before the media. Try to understand it position also. He is also human being!!!