She's just in that angry, rebellious teen phase only it's tinged with things like her hometown being a caricature of its former self while the evil bastards who beat them rule the world. She's not out to hurt anyone except Shinra and she has much less blood on her hands while trying to do that than Barret or the rest of AVALANCHE do.
All she wants is to restore her great home to its true glory.
I can understand not liking Yuffie but she's so...incidental that I can't understand hating her with any kind of passion.