Proposed ban is too broad
We don't ban smoking cessation therapy and things like the patch. We don't ban people from going to Alcoholics Anonymous meetings. We don't ban people from working out at the gym. We don't ban people from seeking mental health treatments. All of these treatments have their bad stories as well - of trainers who hurt their charges. Don't ban anything that looks like "conversion" therapy just because some individuals have done harm, thus doing more harm than what you were intending to resolve.