Yes, that lawsuit. And he is suing them (as opposed to actual researchers who publish contradictory data) because no one will ever see or hear about those researchers and he wants the microphone taken away from people who have it and can spread the word. I hope everyone reads the article you linked to the end and sees that the very paper printing the report (along with the New York Times, National Press Club, Reporters Committee for Freedom of the Press, NBC, Los Angeles Times, et al) joined in an amicus brief to the courts supporting the defendants. For those who don't have time, here's the relevant quote from the article:
"And over the years, the defendants have received similar expressions of support from other sources. In 2014, The Reporters Committee for Freedom of the Press and 26 other organizations — including The Washington Post and other media groups — filed an amicus brief in support of the defendants, suggesting that “defendants were expressing constitutionally protected opinions about both (a) the validity of Mann’s scientific conclusions on climate change and (b) the findings of governmental bodies that had endorsed his views.”
I'm not trying to start a new debate over freedom of speech, but just trying to make the point (probably very poorly) that, as a group, scientists should not be looked on as intellectually, morally or ethically superior to people in general. They have the same nature we all do, and are not above allowing an agenda (again it could be fame, money, status, etc) to effect their work. You get trouble any time you elevate any class of people over another as it pertains to their perceived innate "goodness" or "rightness". I remember when you would never question your Catholic priest, and look how that allowed the continued abuse of many children by some bad apples. That's not meant as a direct comparison, just an example.