This is worst than abnormal in a democracy.

If this was a case of libel against a person, asking for proof (thus source) would still be sketchy, but understandable (the sources are not the primary goal of the discovery, truthfulness of the reporting is).

This is _not_ the case. This is clearly an overreach, and if this was in Europe, I would have helped ngo to present the case in front of the ECHR, as this seems like a human right violation. Do you have an equivalent in the US?