DaddyMakesMeEUHH
(ヽ^ゝ^)ちわー!
I think the reasons Izzy lacks boundaries is because she's overly needy. Needy or codependent people crave love and affection from others. And Izzy definitely lacks love and affection from the other unicorns. Basically what I'm saying is the writers have a lot to build up with her.