It's a good idea in a world where that child is aware of their gender identity (which many people develop far earlier than when puberty starts) and about to start going through irreversible changes. The betrayal of their body is a big part of why trans children have such high rates of suicide.

In any case though, if you're worried about them being too young, why would you be making a stink about a medicine than exists to delay permanent changes in their body? We give it to cis children safely in the case of precocious puberty, it can be stopped and puberty will resume, and it stops a huge source of emotional pain for them.

Just because you don't need it doesn't mean that gender affirming care isn't still healthcare.