^ What Nemena said.
Another factor that I've noticed is that every time a certain type of roleplay becomes a 'fad' (or just particularly popular for an extended period of time), there are just oodles and bunches of people who will dislike and pit themselves against the popular species, just because. (Which, it's really silly, if you ask me.)
While there have always been warriors running around, I do remember when there was a HUGE fad for lions, where the game was almost nothing but lions (this was when I first joined about two years ago), and then it went into a wolf phase, where lions were almost nowhere to be found. And, now it's mostly warriors (not to say there's not any wolves or lions left, which simply isn't true. xD It's really quite diverse, I know.) Either way, it's natural to see tons of their advertisements floating around General in Flourite.
As Nemena said, there's a share of beautifully considerate, creative and original warrior cats out there that are just a joy to roleplay with, and, of course, there's the other players that are attracted to warriors because they've read the books, and they like it.
Granted, I like the books. I like roleplaying as a warrior every now and then. c; There is nothing wrong with warriors, the same way there's really nothing wrong with any other species out there.
The people that say they hate all people who roleplay as warriors are probably just being butthurts about one or two bad experiences they had with some.
Yes, the kitties can be dramatic at times, but there's a much more beautiful side to the Clans, too. So, don't let it get to ya. :3