It’s fear. Fear that the comics are going to somehow be co-opted by film or television folks who don’t understand them or respect them, and then they’ll all be ruined. Because that’s happened a lot over the last 75 years. but that doesn’t stop readers from worrying about it. Plus, there’s also a feeling among the fans that they’re the “true believers” and the movie audiences are just tourists–so their tastes and their preferences should matter more.