you: dazai completely changed his life around when he joined the ada and is now a good human being.
me, an intellectual: a key tenant of dazai’s character is his amorality (his indifference to what is right and what is wrong). the only reason he seems like a good person is because he decided to work for a good cause, that does not mean dazai is now a good person. he has still shown the ability (and willingness) to be callously manipulative, rely on immoral tactics to get results, and be complicit in murder. He also continues to lack remorse for the lives he took while in the mafia.