My points about pronouns are entirely rational. I do have strong feelings on this subject — I think it’s important — but that doesn’t render my arguments irrelevant. You may consider pronouns unimportant, which is fine. I was pointing out why some/many/all trans people do consider them important.
Indeed, all of my criticisms and opinions may be incorrect. I feel pretty confident about them and it appears you may disagree with some or all of them. The fact that we may disagree doesn’t invalidate my opinions or yours.
As far as long-term effects, you are somewhat correct. Hormone blockers have been used to treat precocious puberty for decades and are considered a safe and effective treatment. Blockers are also used in specific long-term cancer prevention. Studies are underway (but have not been concluded) to understand the specific effect of hormone blockers on transgender kids and over possibly a longer period of time than would be typical when treating precocious puberty or cancer.
Similarly, hormones are an effective and safe treatment for any number of rather common conditions but these have generally been used to treat adults, not specifically to treat trans children and not always using cross-sex hormones.
So is this “experimenting” on children? I would say no. The potential effects, including long-term effects, of these treatments are generally well-known and and can be addressed. Is there more to know? Absolutely. The studies (large cohorts over a long period) are happening right now.
However, we absolutely know the effects of not treating gender dysphoric kids: about 40% of them will self-harm or attempt to commit suicide. So doing nothing is clearly not an option.