Well I was born in 1960 - I too was called James until I turned five - and this is my exact story in reverse - so in some ways it seems as if nothing has changed.
I was more or less female from five to 17 - with the help of my parents, who also re-named me Jenny - and then because of sadly developing a lot of facial hair had to pose as male, James again, until my early twenties when I finally retransitioned (I was re-Jenny-rated) and had full SRS.
However what he says is actually not completely true because I have a LOT, and I do mean a LOT, of friends with trans kids, most of whom go to the Tavistock which is a dedicated GIC for children in the UK, and they do often prescribe blockers from 12/13 to 16 and then full HRT. So you can get early help if you get to see the right doctors, and actually talking about a one size fits all national protocol is not entirely right. In many respects the problem is that ther isnt, and that different doctors apply differing standards.
I'm not disputing that his experience was bad, and that changes need to be made. I just think its important to understand that the problem is actually slightly different from what he thinks, and the real problem is that there ISNT a properly binding protcol and that therefore individuals get quite different approaches depending on who they see.