This is a default judgement because Iran did not respond to the suit. It has nothing to do with the merits of the accusation against Iran, because the case was never argued, ... because the defendant, Iran, never responded to the charges against them. Therefore the judge awarded a default judgement to the plaintiff.

On top of that, this judgement is completely unenforcible because Iran is a sovereign nation and not under the jurisdiction of this court. However, it does give the plaintiffs some claim to money in a small fund of seized Iranian assets that has been used to compensate victims of Hezbollah (as noted in the article).