1) They got signed by Disney. That to start off with is a failure.
2) There are four people in their band other than them:
John Taylor - Lead Guitar
Greg Garbowsky - Bass Guitar
Jack Lawless - Drums
Ryan Liestman - Keyboard
The Jonas guys actually only play guitar. Rhythm guitar. In their own band. Apparently Joe Jonas plays drums occasionally, but everyone would really rather he not, seeing as it's a rudimentary caveman beat that a 4th grade band student could achieve. None of them play bass. None. They at least ATTEMPT drums and guitar. But none of them even play bass. Or keyboard.
3) The voice. Sweet Jesus (sorry to the Christians), it's horrible! Honestly, I looked up a song by the Jonas Brothers on YouTube just to see what the hype was all about. I couldn't listen to the whole thing through. His voice is just horrible. And I honestly feel bad for him. If you listen a little more into the vocals, whoever lead vocals is actually has some talent. He isn't that bad of a singer. Honestly, he's pretty good. But something (possibly the tighter than skin pants) is making him contort his voice and go so ridiculously high and whatnot that it just sounds lousy. He actually has a bit of talent, and I kind of feel bad that he has to be dragged down by the band's style and the rest of the lack of talent. Only, I don't. Because he is in the band of his own choice, and sucks at guitar.
4) People defend them for "being so young." Honestly, I've heard you Jonas fans. "LEVE DEM ALONE!!1!! THEIR RLY YUNG AND HAV WAY MOR TALENT THEN U EVR WILL!!!1!!235!! UR JUST JEALOUS!!!!eleven!!!" Really, now? I think the oldest was seventeen at the release of their first album? Metallica was eighteen when they released "Hit The Lights" (their first demo.) [EDIT: I was wrong. Metallica was 15. And I believe it was called "No Life 'Till Leather"] Don't try to play the young card. I personally know musicians infinitely more talented than these kids who are way younger. I am totally jealous of their inability to solo, sing, or have children for wearing too tight of pants. Yep. You just hit the nail on the head, Jonas fans.
5) The tight pants and the hair. The pants are castrating them. They spend more time on their hair than their music. Enough said.
6) Even with all of this...the lack of talent, annoying fans, inability to play anything more complicated than "Happy Birthday," and horribly tight pants...I don't think most people would have a problem with them. Most people don't go looking for bands to hate and pick fights with fans. The horrible part is that they're popular despite all of this. People like this garbage. People listen to this garbage. People pay to see this garbage. The fact is that they are more popular and widespread than tons of far more talented bands who deserve a lot more acclaim than they're getting. It's the fact that they're stealing the spotlight from far more worthy people.

Overall, the music is lousy, they have a horrible image, and they shouldn't be popular.

I could write more, but for now I think that's enough to get some fans to yell at me.