Well I'm a sniper on almost every shooter I play, but I'm not a camper, I move around and defend allies when their going to objectives, AND I get flamed for it... I don't know why people hate snipers.
Example: on BFBC:2 I was covering a flag by taking out drivers to let our tanks get them so people flamed my inbox, but I don't see why, on battlefield you have to adjust bullet drop, their speed and distance away. battlefield you need skill to be a sniper, so my thoughts are people who flame snipers usually hate it because they can take the time to aim and fire instead to holding down the mouse button/right bumper until the object in front of you dies.
So i just laugh at flamers/troll and YES I do believe that snipers get a bad rap, but not just because of campers, but because of their patience and skill required to kill someone.