Based on the situation indicated in the selection, we could conclude that Katie belongs to the conventional level of moral development. In addition, Katie has already this ability to judge on what is right and what is wrong as what her mother has taught her. These level of moral development belongs to adults already.
If Cathy blames her history teacher for her poor performance on a history test she is most likely engaging in: Self serving bias
Self serving bias refers to a way of thinking that always perceive ourself in a positive manner. People with self-serving bias often willing to over look their own mistakes in order to avoid the feeling of failure, which cause them to constantly blame other people for their own mistake.
No we ban them for protection purposes so that ordinary scientists and citizens cant get their hands on them and use them against our own populous