The bad thing about reorientation therapy/reparative therapy is its association with Christianity. These Christian bigots try to enforce their personal interpretation of religion on gays who do no want to change themselves. Doing so is utterly ludicrous, insensitive and inhuman.
This scenario has become an issue in countries like the united states, where a group of Christians thinks that they have the sole access to an ultimate truth. If there is a God, god would want people to be happy.
There is absolutely nothing immoral about being gay. If someone wants to change due to their religious beliefs there is nothing wrong about that too. There are so many other reasons that would propel someone to seek change. Change is possible for most of the people. Change cannot be forced upon anyone and it doesn't work that way. If a therapist tries to make a patient feel guilty about being gay, he/she is not an ethical therapist. Therapist should leave aside their personal, religious beliefs on such sensitive issues.
There are many non-Christian, former Christian/catholic, and Buddhist (which is spreading rapidly among the psychological and medical community) who helps people to develop their heterosexual potentials.
Some may not even change but as a result of the therapy will become sane, better homosexuals. But change is possible, if someone wants to change.
Reparative therapy is not the only way to help patients develop their heterosexual potential. Therapists have their own ways, with which they help patients. Gender affirmative therapy is another such form of therapy. One type of therapy may not work for everyone. Often therapists do not label their form of psychological assistance as such.