The problem is that for a teen experiencing mixed feelings as their sexuality develops, it is often going to be unclear for a time how they will eventually feel comfortable describing themselves.
The same person might end up describing themselves as very much a woman, who prefers to present in a "masculine" way and has tastes and preferences which are close to male stereotypes than female, or may end up deciding to describe themselves as a man who happens to have been accidentally born with female organs, which they may or may not want to have removed surgically. Or they may describe themselves as non-binary or some other innovative identity. (obviously similar scenarios could equally occur swapping around male and female in the above description for a biologically male person). It is entirely normal and expected that someone might "try on" more than one of these options during adolesence and early adulthood before they find a way to describe and present themselves that feels comfortable and authentic.
When it comes to conversion therapy, anyone who is a wholehearted supporter of trans identities might consider that asking someone to consider whether they aren't actually trans, but that one of the other options might suit them better, sounds like it could be "conversion therapy" whereas to other people, suggesting to a butch lesbian girl that she would fit into the world better as a heterosexual man also sounds like "conversion therapy".
The waters are further muddied with concepts like the "Cotton ceiling" - i.e. telling lesbian girls that if they don't accept fellow lesbians who just happen to have a penis into their dating pool, they are being transphobic. To some, that is conversion therapy by another name as it is forcing someone to effectively be bisexual/pansexual rather than homosexual.
Conversion therapy is real and has caused immense damage over centuries - gay people have been subjected to awful "treatments" to make them become heterosexual. Some have claimed it "worked" and they are "cured". Others have been deeply traumatised and damaged. So legislation is certainly needed, but how it should be worded is not clearcut or obvious and whatever way it is worded, there are going to be some groups who think it is wrong. This shouldn't be an excuse to do nothing, but I can totally understand why it is taking a long time to make it happen.