I think Ninjago and movie treat Cole poorly. Because of the lines in the movie is less. And Cole turned into a ghost. He fell into the darkness. Especially the worst part. People just disliking him. Some audience and the show itself treat him dirty.😢
You do realize him turning into a ghost and him falling in season 10 was not because the writers dislike him, it's because they wanted Cole to have an arc of his own and have something to do