All the bands in the world get the most pointless hate. Honestly, how many people here actually still buy albums and judge bands based on albums rather than individual Radio Singles the record labels push to make money?
To actually say you hate a band and have good reason for it, you'd have to either have proof that every song they come up with in their albums is about the same, or have listened to all of their material. I don't like Linkin Park's new stuff, but I certainly think they're still a good band even if Meteora and Hybrid Theory were the highlights of their material, and I have listened to all of Minutes to Midnight (Was that even its name?) (I have not, however, bought A Thousand Suns to listen to).
On the other hand, I can safely say Papa Roach is shit, because I have bought all their past albums since Infest, and everything seemed to be going well, until the Paramour Sessions album, which was pretty crappy. I bought Metamorphosis thinking they had gone back to their roots with a new twist after listening to Hollywood Whore, but it really is showing that they are just moving with what's popular, rather than fighting for a genre that they believe is cool.
Finally, I think I'd say Metallica receives a lot of crap even though they don't deserve it. Sure, they're a sinking ship right now, and Loaded - Reloaded and even The Black Album weren't the best Metallica had to offer, but live they still kick ass, and just as long as they don't get a shitty producer for the new album, I think it's going to be pretty good.
I think there's a difference between hating a band and respecting it, and just plain hating a band. I hate Bieber, I hate Gaga, and I hate several other pop acts. I also hate most rappers, because they destroyed a genre of music that actually had something to say, other than the number of women you can score with in one night. But I respect them, because I know those people put at least some effort into it, even if it is commercial. And several times, the album itself has a lot of songs that they put their heart and soul into, but because they aren't considered to be potential of commercial success, they don't pay any attention to that. Not to mention that most music listeners now just go on iTunes, get the one song that they heard by chance on the radio, and forget the rest of the tracks on the CD. And if they never listen to them on radio again, they just forget about them.
I know this mostly from personal experience, since my favorite band, Ash, were forgotten after their first and only #1 album in the UK, even though now they're the ones who have come up with actually revolutionary ways to distribute music to people who now just care about individual songs. They sent the label to hell, and just decided to make their own label with their own recording studio, and handle their stuff pretty much single-handedly.
Bands/Solo Artists I don't respect: Ke$ha (the name is even stupid), Katy Perry, and a few others that have just slipped my mind.
Edit: Also, all the bands that get hate for not being revolutionary. If you go to a concert of students of modern music theory, the things they compose are bizarre, and even bands like Deftones and Megadeth sound commercial compared to the craziness that is actually revolutionary music.
