'Cept in this case it was runwayfinder who was engaged in theft, and Flightprep simply asserted their rights not to be stolen from.
RunwayFinder was not engaged in theft until the patent was issued in 2009. Altho the claim "ignorance of the law is no excuse" it's reasonable to believe that RunwayFinder was not aware of the final decision on the patent. And I'll guess that until FlightPrep started all this, RunwayFinder had no reason to believe it was in violation of the patent.