Because Opus Dei has been secretive in the past,
And let it be secretative in the future as well
it allows itself to be defined by ODAN and Ron Howard.
No, it does not allow itself to be defined by them. They are defined by the Gospel.
And if they want to change public opinion, they have to define themselves as assertively as others define them.
You are assuming they actually give a care about the opinions of men. The Gospel is not according to the opinions of men. Jesus didn't go around asking what people thought of him. He did not care. Neither should Opus Dei.