This has recently started to change, because people recognize how unbelievable it is, and because accusers can have larger voices in today's media environment.
Roy Moore is using the old playbook. If it succeeds, in the face of all evidence, it will be a very bad thing.
If the offenders think they can keep secrets, or that no one will care, there is no disincentive to continuing the behaviour. Aside from the whole morality problem of being an awful person, which seems not to be a big factor for some people.
It's possible that the Moore situation, however it breaks, will only apply to political figures, or only in Alabama. But the idea is chilling.
For instance, whatever else happens, I don't think Moore will win another primary in Alabama.
I agree that this election in Alabama is difficult to generalize from though, there are many factors at play. Still, I'd prefer less ambiguity here.
So while it's concerning, and I'd like to see it fixed, it's kind of orthogonal to this particular issue, and affects e.g. climate change, the impacts of the tax bill, the healthcare discussion and so on.
I understand your point and am hopeful that at some point it goes the other way and the rightfully accused say "ugh...better to just admit it and try to move on with my life too."
I am, however, concerned that we'll see more people that choose to simply deny credible allegations in the face of solid evidence (and rally others to do the same).