In such a case, the author of the PDF can be held responsible.

Radical idea: let’s hold the reader responsible for the actions they take from the material.

So we should hold my grandmother responsible for the phishing emails she gets? Hmm.

Radical rebuttal of this idea: if you hire an assassin then you are responsible too (even more so, actually), even if you only told them stuff over the phone.

I don’t see the connection. Publishing != hiring.

Then I don't see the connection in your idea. Answering questions != publishing.

Twitter does it at scale.