Okay, well first of all, this person is wearing a stupid hat.
Secondly, it's very easy to make a video insulting someone, or to be part of the bandwagon of hate against her, but this guy is also being full of himself.
Not to mention he's a black guy who sounds camper than Julian Clary, but this is some 13 year old girl he's insulting. He's like, what? 18? There's nothing brave about it, if you don't like the song then simply don't watch it/listen to it.
The internet can be a cruel place and everyone ganging up on her is just a bully.