There is nothing wrong with guys who are after that at her age ... They are not mature enough yet and are just beginning to explore their sexuality 
It is when they grow up and are still after dumb, slutty girls is when I look down at them...
Nothing wrong, yes, but do you know just how knowledgeable some kids already are? They try to act older than they actually are. Then, after a few 'relationships' they (boys and girls) act like they have impeccable wisdom and have been through the tuff tymeszszZZzz. You can be experimental of course, naturally, but never have teenagers been so over-the-top and extreme in their experimentation of sexuality and self-image, to the point where it's openly questionable and debatable.
Going off of Mech's point of false pretense, the mind is also very vulnerable and in many senses, naive. So this, coupled with increased levels of sexual and sensual experimentation can lead to a very lost and confused mind; too young to be experiencing such emotions..
So, my conclusion is, this girl is equally as vulnerable herself, probably releasing tension and frustration from her inner self. Everyone feels outcast and deals with with peer pressure at this stage in their lives. The only difference is she voiced her thoughts..on Youtube..to the world..I would have done it in my mind 
