She may very well be manipulating the situation and at the same time, her need is no less real. It doesn't mean you have to cater to it though.

I don't know her history other than the bit you give and I can see how perhaps she might feel desperate for what she is missing. When we're children, ideally we get our attention from our parents and if our parents are health we learn from an early age how to get attention in a healthy, appropriate way (because everyone needs attention in some form and amount). If that doesn't happen... well I guess I can see this as not unlike a toddler acting out in a bid for attention because something inside her is empty. Idk. Can't say for sure.

It doesn't give her the right to treat you poorly nor does it mean you have to feel okay about the situation. It doesn't sound like she wants to listen and beating your head against the wall isn't going to do much good anyway.