Other than their assertion that the stability and proper functioning of their websites is under threat, what is interesting to note are the particulars of claim: a violation of the First Amendment, the Property Clause of U.S. Constitution and the Administrative Procedure Act.
These fellas are loaded for bear! The plaintiffs used language from the 2012 IANA contract as evidence the USG has a property interest; see P.6 of the pleading. And used the threat from NTIA of a non-renewal of the 2012 IANA Contract as evidence that ICANN would be a bad steward, undermining 'predictability, certainty'. They would not wish to do away with the 'protections' that come from a federal steward against 'unchecked' control of ICANN, who they say have a 'documented history of ignoring or operating outside of its
governing bylaws'.
They also forum-shopped; some who watch these things say quite a few of the judges in the Southern District of Texas are reliably anti-[Obama] Administration.
-Carlton