If a crusade is a religious war against non-Christians, then what might the religious war against the Cathers have been?
They were certainly as Christian as anybody else around in their time.
It's about time for everyone to just quit trying to justify the war against the Cathers.
The religious war against the Cathars was indeed considered a crusade. It was called the "Albigensian Crusade." William of Tudela's epic on this crusade is entitled "Chanson de la Croisade contre les Albigeois".