Okay, I disagree with this for several reasons.

1. I think it's unfair to suggest that this mother "let things get out of hand" when gender identity ideology is everywhere. It's super popular among the younger generations, and in many social contexts, teens/young adults are socially excluded and shamed for not participating in it. Those are some powerful forces pressuring this woman's daughter to get deep into gender identity beliefs, and broadly speaking, that kind of societal pressure on teenagers near impossible for parents to prevent. No matter how controlling the mother is, her daughter will still know that gender identity is "cool" among her peers and will be pressured to participate in it... a parent can't erase that powerful social pressure just by being acting more controlling.

2. Being controlling is counterproductive for at least one glaringly huge reason: the child's gonna turn 18 and then the parent can't control anymore... what then? If the parent's obsessive controlling was the only thing preventing the child from medically transitioning-- then the child is just going to go transition when they're 18! That's still bad. Sure, they won't be harming their body as much as if they transitioned at, say, 12 or 14 years old, but medical transition still has serious health risks even for adults who transition.