1. They just don't enjoy the music.
2. They hate the fact that there are several unintelligent people that think they are the greatest band ever.
3. They heard a rumor that they speed up their songs and blindly believe it.
4. They dislike all mainstream music.
5. They think it sounds too much like video game metal.
6. Their friends dislike the band and they are merely trying to fit it.
7. They think that their only famous because of Guitar Hero 3. (Not gonna lie, that IS where they got alot of their popularity from.)
There could be several more reasons.
Said hater could be arrogant or passive about their dislike. Most arrogant haters will verbally attack Dragonforce fans saying that they listen to crap music.
Passive Dragonforce Hater: I don't really care for that band. But I'm glad you had fun. Wanna go see Trivium next month?
2. Me: Yeah, that Dragonforce concert was pretty awesome last night. Lotta misled ki...
Arrogant Dragonforce Hater: *interupts* Oh my god, you like Dragonforce? You know they speed up their songs and can't play good live right? Your such a faggot. Go listen to some real metal like Killswitch Engage or Dream Theater.
Me: Um...I actually like both of those bands.
Arrogant Dragonforce hater: Oh....well Dragonforce still sucks the big hairy "I'm only famous because of guitar hero" penis.
Kid B: Oh, I went to a Dragonforce concert. They were pretty dec-
Kid A: OH! MY! GOD! You like Dragonforce, that is so gay! You know they only became famous due to Guitar Hero?
Kid B: Well, yes but-
Kid A: They only have one song you know?!
Kid B: What about Fury of the Storm or Operation ground and p-
Kid A: You know they speed up their songs?!
Kid B: You don't have any proof of that. You probably just read it on the internet.
Kid A: THAT DOESN"T MATTER, THEY'RE STILL GAY! DRAGONFORCE ARE FAGS! *Screams then convulses on the ground*
Kid B:........Are you alright? Dude? Dragonforce hater?
Real Metal Head (Dragonforce Hater): Fuck off, retard.