I think it should be illegal for adults too, in the same way it is illegal for them to have a doctor amputate their working arm because they “identify” as the killer from The Fugitive.

Part of the reason they are able to come after the kids with this is because we already conceded that it is okay for adults. Also, once you allow it for adults, you are by extension allowing those same adults to enter your society and start influencing children in thousands of subtle ways.