Hi! Good question, because jurisdictional issues are complicated. There are two different questions here, one is why this is in federal (as opposed to state) court. The plaintiff was able to argue that the case should be in federal court because the value of the case is more than $70,000 and because the plaintiff and defendant live in different states. As for why federal court in DC, that’s a little more tenuous. The plaintiff argues that Rudy is a DC lawyer who committed the defamation while he was in DC (at least partly) for a DC based client (Trump). Kinda weak but when Giuliani didn’t show up in court you don’t need a whole lot.
Venue sounds appealable to me