The problem lies in the medical fact that you cannot change biology with talk therapy. If that were possible, transgender people would not be taking hormones and undergoing expensive and risky surgeries.
Professional organizations, such as the American Psychiatric Association and the American Psychological Association, all agree. The problem is when people whose only agenda is ideological, with no training in talk therapy, are permitted to engage in the practice without a license. They are exempt due to religious grounds. Religious counseling is permitted.
Free speech does not apply in talk therapy. That has been decided. Professional conduct is licensed and regulated for a reason. Religious exemption is a loophole in regulations designed to protect the patient.
Forcing someone to undergo such therapy without a court order is abuse, whether they are a minor or not.