I can see, sort of, why there was no formal investigation. But, but...in a well-run organisation that tries to be fair and also have an environment where no one is harassed and harassment is punished, people should not have ignored rumours, certainly not persistent ones.
The women would have had someone to talk to, or been approached and asked if they were ok (I have that role in my workplace: counsellor/recipient of complaints kind of thing. If someone told me rumours I would have to follow it up, if only to let a potential complainant know the grievance procedure and be a sounding board).
The man would have been spoken to, even if on a fairly non-committal basis to remind him of anti-harassment policy etc. (I genuinely think in my workplace the top man would do this. He is very good at 'iron fist in velvet glove' coded chats and a groper would get the message there was no cover-up going to be implemented by other men on his behalf. But I accept I'm probably very lucky in where I work).
It all gets the message across: we don't tolerate this kind of thing, if it is happening we will deal with it, please use official avenues rather than gossiping etc.
Instead it all seems to have been buried. Unless the women made formal complaints no one was at all interested.