I can't work out what it is that I'm missing here. Whether we agree with it or not, some males are more comfortable living as female and vice versa. To my knowledge, they don't tend to flip-flop between genders.
If a boy lives as a girl, and join a Rainbows/Brownies etc group, does she then become a lesbian and put the other girls at risk? Or is it feared that although she lives as a girl, and has been accepted into a group as a girl, as soon as she comes near other girls, the male hormones take over and she become a raging sex pest/potential rapist?
If she joins the troupe as a girl, and is accepted as a girl, and participates as a girl, then why does anyone need to know that she started life as a boy.
I wonder how any of you would feel if your much loved grandsons were effectively seen as a safeguarding risk if he decides he is more comfortable in a girls' skin and was excluded from activities because the rest of his peers were girls? Would you still be saying he shouldn't be welcomed into a group because he wasn't born with the right genetalia? Would you be thinking that he posed a risk to girls?