My PoV is that the link itself IS irrelevant; you can just look at whether it inflicted harm to the owners of those credit cards, and in this case it obviously did not - the information was already available.
Yeah, that's one of the things that would make pasting a link just fine in my opinion/analysis, is if that data were already publically-known (and not otherwise legally restricted somehow). I'm not diving into 40 pages of indictments to research again, court PDFs are driving me batty, but to the extent that information was already out there somehow I don't see justification for charging Barrett for simply pointing that out.