Why do people hate cheerleading?

Ok, so I am a cheerleader and people always say they are so dumb and stupid. You have to maintain good grades to be a cheerleader!! I have all A's!! Most people on my squad do! And they say they are mean brats, but I am cheer captain and i'm not. People look up to me and I donate to charity and such. They say it isn't a " sport " which I think it is. It's very hard ( yet fun ). I feel so sad when people say it's not. :( :( :( :( :( :(