Considering there is a decent amount of adults who regret having hormone replacement therapy at too young of an age, resulting in permanent bodily changes they cannot reverse, I agree with this decision. Young children and adolescents can be so impressionable and will copy so much of what they see on social media, whilst trying to discover who they are as a person, that it can lead them down a path that might not be right/suitable for them.
When I was young, I was referred to as a tomboy a lot, but didn't think much more of it because social media, and the openness of LGBT, wasn't much of a thing then. Nowadays, it feels as though if a girl is referred to as a tomboy, she must be either gay and/or trans, so they're then socially moulded into this idea that a girl cannot be a tomboy without being one or two of those things. But if we stopped gendering hobbies/interests, maybe one day, the label of 'tomboy' will die out eventually. I thankfully realised that I can be a woman and be interested in a variety of things, and wear whatever I wish, but still identify as a woman. Society seems so quick to gender someone based solely on their appearance, and that's why I worry about HRT being available to children.
The brain doesn't stop developing until your mid twenties. No-one knows who they really are and what they truly want out of life in their adolescent years; the brain is going through so much change that I feel it's dangerous for them to make such a life changing decision. It's why children can't get tattoos, except there is some way of reversing those.
Also, considering the financial burden on the NHS already, and the almost complete lack of mental health care, this feels like an expense that can be put on the backburner for a while until better treatments/studies come to fruition about the long term effects of these medications on children, and maybe when society stopped being so pushy on gender and stereotypes.
However, I completely understand why the trans community aren't happy with this.