Re: who is at fault...
No one is at fault.... a girl dressing in tight clothes is dressing the way she wants to without hurting anyone just like a woman wearing (a) hijab and a guy straining his neck is doing nothing that is hurting anyone... why judge then or call them names just because you don't live that way?
They are only hurting themselves and in the end it is between them and God..... and I don't think God needs your opinion to help him judge their actions.....
Aside from all that.... self-esteem would be my guess for accentuating her body for the attention, negative or positive, as opposed to just dressing for comfort and ease.....