Seems like he's making fun of what a psychologist is. I think it's morally wrong because some people need real mental health. If Mumford had never been arrested, what would have happened if he had been asked to treat someone with a serious mental illness? This could have ended extremely badly. Mental disorders such as schizophrenia can be very serious and, in some cases, dangerous. With schizophrenia, people tend to have hallucinations. This can drive them crazy and make them think someone is telling them to do something. If Doc had met someone like this, he wouldn't have known what to do and things could have gotten worse. People suffering from depression also need help, as some of them might need serious help. Doc makes mental illnesses like depression and anxiety seem unimportant and unreal. He thinks people simply lack attention and that's why they feel this way. If he had used his approach of just listening to people talk, a person suffering from depression might have attempted suicide because he wasn't actually giving them the help they needed. Doc doesn't take into account how serious psychology can get and he was lucky not to meet anyone with serious problems.