I'm sorry to hear that, and good for your sister, but not everyone does. And using your own sister's story of abuse to minimize the suffering of victims who didn't make the same choice to to notify the authorities immediately isn't very cash money of you.
The fact that it can sometimes take years and years for victims to speak up, and for the law to hold perpetrators accountable for sexual assault, is apparent in the stories of abuse that have come out of organizations like the Catholic Church and the Boy Scouts, let alone individual rapists such as Weinstein, Jeffrey Epstein, and the like.
Weinstein had over 100+ public accusations against him before he was finally found guilty and convicted in criminal court -- on just a couple counts, and just a couple months ago. There were a lot of hush-money payments and threats of violence and professional reprisal keeping his victims silent along the way.
https://www.usatoday.com/story/life/people/2017/10/27/weinstein-scandal-complete-list-accusers/804663001/
Who knows how many Epstein abused before he was finally brought to "justice," though he killed himself (conspiracy theories notwithstanding) before he could be tried and convicted.
The wheels of justice turn only if we let them. In the meantime, we should withhold judgment and not prematurely grasp at exonerating explanations.