I am also the parent of a trans child who is now a trans adult.
It's so simplistic to blame the parents and accuse them of abuse. This is rarely the case.
We have children who are struggling through something we dont fully understand, there is no mental health help available. If you watch your child struggling for years, self harming, education suffering, possibly suicidal, eventually get an appointment with someone who should be able to help, and they offer you blockers, it would be very hard to refuse and allow your child to keep suffering in that way when a medical professional is there offering a solution.
Often the short term is so scary, we don't know if there will be a long term for our children and do what we can, and, unfortunately have to think about the consequences later once our child's mental health has stabilised a bit.
It's a balancing act for parents and we don't always make ideal choices.
I really don't think blockers, or this trial are ethical, but I absolutely get why parents do it.