okay i know hypnotists say you won't do anything against your morals, but if the hypnotist told you that someone killed your family then wouldn't your morals change? or if they told you that you were a doctor and needed to give heart surgery wouldnt you? how is this different then them telling you something harmless like your really cold or you forgot your last name?

This is a great question, and I often raise a similar point when teaching hypnosis to students. I believe it's just a comforting myth that you can't get a person to cause harm (or rob a bank, etc.) using hypnosis, for exactly the reason you describe. If hypnosis can cause belief change, hypnosis can cause delusions, and delusions can cause people to act in harmful ways. I believe that, as hypnotherapists, we need to be vigilant of the risks in order to perform hypnosis safely and ethically.