I suppose that this is only an allegation at the moment, although other similar allegations about the same organisation pushing a left-wing agenda at the expense of education have been made, which makes the whole thing more plausible (plus there is Azathoth's original allegation).

Asking an adult if they know anyone who is trapped is ok. The problem is that asking a 10 year old primes them with a concept they would not previously have had. If there is some sort of train of thought one can go down, which ends with 'help I'm trapped in the wrong body' when they would otherwise not have had this problem, then you do not prompt them to start this train of thought. For mostly the same reason, you don't ask children "do your friends drink vodka?".

Essentially, its conceivably possible that the idea of transsexualism poses an information hazard to children.