I'm afraid I disagree. Rin doesn't owe Obito her feelings. She isn't obliged to like him. You make it seem obligatory to love someone back who isn't blood related.
The girl was like 13 obviosly she will just go for the eye candy coolness(kakashi), its a typical hischool shit where they all get used and end up doing porn for a living or finally realise their mistake and take some poor blinded fello(obito).
luckily for obito she died of a broken heart :hooray: