True, but the point of puberty blockers is to let the child decide rather then force them into a decision that's worse later on.
I understand the rationale behind them...the idea being that if a biological male has gender dysphoria, and chooses to live as a female, and that doesn't change with age, it's a lot easier to pass as a convincing female if the effects of male puberty haven't taken their effect.
The issues with allowing people so young to make those choices is that
A) many young people have short term focus without thinking about the long term, and given that those drugs can carry serious risks long term effects, combined with the fact that well over 60% of youths diagnosed with gender dysphoria desist on their own before age 20 completely absent of any drugs or outside therapy or influences, allowing an elementary school kid to take those kinds of drugs can be dangerous and unethical
B) It's only really applicable the M-t-F scenario and not the F-t-M scenario. Once a boy hits puberty and starts growing much larger than a female would, broad shoulders, etc... it's a little tougher transition. However, F-t-M hormone therapy can happen at relatively any point during (or even after) puberty without any sort of major difference in outcome.
Obviously, there are times when it's pretty easy to tell when someone is transgender in a M-t-F situation.
However, for F-t-M, that can happen at pretty much any point in early adulthood if the person decides they want to pursue that option and nobody would the wiser afterwards.
(all examples of biological females that decided to transition to male after already reaching adulthood, and nobody walking down the street would even be able to tell if they saw them.)