This protects the privacy of victims, offenders and innocent suspects. All of them should have a right to privacy, except convicted offenders in matters affecting the public.
No. Accusations (and court proceedings) need to default to being public. This is an important check on the power of prosecutors and judges.
It's as much intended to protect the public from the government pretending to do things about problems that it is not doing; if prosecution is secret, government can more easily claim it is making good faith efforts when it is not then when the public can see what they are presenting at trial.
Interesting idea; that does seem like a reasonable compromise (subject to safeguards against coercion by prosecutors and similar abuse, of course).