I feel like many here have the wrong attitude.
I think your attitude is commendable, and comes from the right place, which is more than I can say for most eager to rip the man apart. But in addition to what
@Euclid eloquently responded, I'll add that the reason abusers are able to abuse so many before they are found out is at least in part because so many are so slow to believe victims when they do come forward, even for the most noble of reasons.
I'll note there was no thread discussing this matter until he was no longer alive, despite it being one of the biggest stories in the frum world over the past while. I've considered starting a thread just asking why it didn't exist. I'm genuinely curious, even if I think we were better off without it.
As I said before, I don't think every DDFer needs to protest individually, but when the "talk of the town" is to whitewash his actions just because he is no longer alive, that is sending a loud and clear message to his victims, and in turn ensuring the next abuser's victims remain silent and cause even more to get hurt.
And as for waiting for rabanim to issue such statements, sad to say that hasn't really happened till now, and it's tough to envision a day it does happen.
Imagine a court case where the pews were filled with supporters of the victims rather than the accused.