Conversion therapy does significant harm to those who are least able to protect themselves. While restricting the freedom of people should be viewed cautiously, the times when it is most appropriate are those times when the State can step in to protect the weak.  We make it illegal for parents to abuse their children, even those who do so under the guise of discipline, because we recognize that the State has a moral duty to protect people from others.  Conversion therapy is abusive, it has been shown to lead to significant harm both in the immediate and in the long-term, and it tries to solve a problem that doesn't exist - studies repeatedly find that the suffering of LGBT children and teens comes from the social stigma and the bullying, and when those teens are put in supportive environments they thrive.  Conversion therapy only serves to further stigmatize and shame those children who are forced into it, and the State has a strong interest in protecting them from that.