As someone said above, you got off on the wrong foot and stayed there. As I read your account, I, too, am uncomfortable with your performance. Everyone (other nurses, your instructors, etc.) are just people and no one is perfect. None of the people you work with: you future managers, etc., are going to manage you perfectly, like a TV lawyer. You need to bring your own common sense and not rely on others to tell you exactly how to behave professionally.
Your instructors are acting on how uncomfortable your performance is making them and their efforts to get you off the floor are imprecise and not exactly perfect. I would not want to be responsible for managing you and would not trust you to care for my loved one, and no one at your school is interested in taking on that kind of liability. There is literally no good reason for them to support you at this point.
Yes, expectations were poorly communicated: "what happens on the unit stays on the unit" was not clear to you. Unfortunately, telling you to grow up, take responsibility, be engaged, and behave professionally is also vague and probably not helpful to you. But that is how life is.