What explains the silence from Amanda Palmer? I guess they've got a kid together, so that might explain why she doesn't want it out in the open.
That also might explain the silence of his friends like Tori Amos. If they feel they are protecting NG's young kid, that might be a good reason to say nothing.
As far as actors and professional collaborators go, I suspect it's purely self-interest. They don't want to lose work and favour. As soon as it looks like NG is over, they'll be jumping on that bandwagon to talk about how they are appalled and horrified. And as long as the mainstream press are hands off, they can justify saying, well we didn't know/didn't think it was anything more than rumours.