I wonder it is because people like to think they are, and but some time fear they are not.. backing the winning team.. where "team" represent your art, your thing, your position, your party, your side or favourite, your what ever??
1. Is true right that where you are on the de facto winning team you have not anything to prove nor to argue, well unless you lack magnanimity, yes?
2. Is only where you are admit self-doubt that your team is the winning team, that there is need to elevate your position and one way to feel elevation of your position is to negate, decry, degrade or seek to invalidate the other thing, the opposing thing.. what appear as hate I would wonder could this be overzealous or fanatical debasing of that opposing thing for this reason?? cannot be sure..
You know we see this zealotry and debasing of the opposing thing in most field of human endeavour, yes?? is not just martial arts and but any interest, hobby, among academics even notable scientists, celebrity and fans of celebrity, among proselytes of religions and parties, or nationalists across and within borders.. what ever.. is wide spread human practice.. martial artists are susceptible as any one else??