That's not technically correct, although it's definitely the most moral approach in the circumstances.

I'm not a lawyer, but I don't think that's what this announcement means.

It's not legal, but it's always moral to pirate the output of scumbag leeches.

Why not? If Fables is public domain shouldn't I be allowed to make scans of my copies and share them?

I was talking in a general sense there.

Also, DC does have rights to past output, the "new" public domain rights are for the general public to create stories in the universe using the unique creative elements that Willingham formerly retained copyright for, as per his contract.

Willingham and DC are still bound by the contract between them. But, the rest of the world is not. That doesn't mean that DC won't still try to strong-arm anyone who wishes to make their own Fables stories, it just means that Willingham has given the copyrights that he retained as per contract to the general public.

IANAL, this is layman analysis, etc.

Not the pdfs created by DC. But someone probably can republish Fables, maybe or maybe not using the DC version as a source, and you can download that legally.