Just as there is a push for greater transparency in research (Google, "transparency in academia"), this ruling comes along.
Just so we're clear: if your research is pretty benign, fine, keep your work secret. If however, your research promises great change to your field OR WORSE motivates changes to public policy and the spending of public money, then it is your duty to practice transparency until it hurts.
Fame (esp. academic fame) has a price, scrutiny. It is a measure of the character of Mann that law is being used to defend against proper scrutiny of his work. A prideful man, but a poor academic.