Gay conversion therapy is a moronic idea.
Doesn't mean we have to go ban it. Not sure why people seem to think that just because they disagree with something means that they have to go ahead and legislate their ideas to the rest of the state/country.
Stop banning things.
What separates the libertarian from the anarchist is the belief that the government should at least exist in order to protect individual liberties. Actions which harm the freedom of other individuals are still illegal in the libertarian model. This is the morality that makes murder against the law--and this too.
You should be all for banning gay conversion therapy because it inflicts suffering on individuals and infringes their right to live freely. You are violating your own ideology by not wanting this law.