I used to be like her in primary school, everyone hated me and bullied me because of it. Don't take her words to heart, this is genuine advice. You're gonna be a terrible person like this.
Basically I took the saying "Treat others the way you want to be treated" without understanding what its essence is. I thought that my way of having fun was fun when in reality it's just annoying other people. Since other people don't act to me the same way I act to them, I thought that I had to act harder to prove my point of the saying I didn't even fully understand and obviously no one did cause that's just terrible behaviour.
She doesn't know how it feels to have a possessive boyfriend and how taxing that would be so she's just saying things she don't even understand.