One of the questions frequently asked about the Ozawa Ichiro situation is why, if he is as clean (keppaku) as he claims he is, does he not go before the Diet, either in camera in the Ethics Committee or before the cameras in sworn testimony, to tell his side of the story. For some, this reticence is evidence that he is indeed hiding something (en) -- that he is afraid something will pop out under the pressure of questions from the opposition.
I can think of one other reason why Ozawa Ichiro would see little reason for his appearing in the Diet: it benefits his rivals in the party. As long as he is around but not saying anything, the party's image gets tarnished and his rivals, who are the ones in control of the party and the government, struggle to get anything done. If he talks, no matter the outcome -- i.e., the testimony finds Ozawa without fault, finds him rife with inconsistencies or finds the smoking gun -- his rivals benefit, the cloud having been lifted off the party.
Put yourself in Ozawa's position. Given the chance that something heretofore ignored might suddenly come to the fore or that the only ones who really benefit from your testimony are your rivals in the party, would you testify?
As for Ozawa's attitude problem, as was demonstrated in his responses to questions at his press conference of October 6, the simplest explanation is that he is a certain part of the male anatomy. Whether he is congenitally a certain part of the male anatomy, or came to develop his certain part of the male anatomynishness under the tutelage of Tanaka Kakuei and Kanemaru Shin, both of whose certain part of the male anatomynishness was truly epic, or that his having to pass kidney stones (en) plays a part, the result is disastrous for his public image, no matter the merits of the case against him.