I don't think kids socially transitioned are any more "locked-in" than kids who are told their gender is their birth sex and others use corresponding pronouns.

I don’t think it is more “locked-in” either, but I think it matters what you think is better too. Many of us feel like it is better for someone to be able to live as their sex and not have to alter their bodies in ways that sterilize them, decrease their life expectancy, and require permanent medication. If someone can successfully be “locked-in” to accepting their sex, that seems like a good outcome. If someone needs to transition to be okay, trust me, no amount of not affirming will make that go away. That person will still be able to transition, but we won’t be creating life-long medical patients from people who would have otherwise desisted. That’s how I feel about it at least. Transition should be treated as the last resort so it’s dangerous to do social transition at early ages because it leads to medicalization almost all the time. That isn’t what we should want for kids and it’s super sus to me that many seem to want that.