Good question. I was wondering that myself. If changing homosexual orientation to hetero is possible, then it should be possible to change pedophiles to "normal". I think it's been tried. Or maybe not using the same methods.
It may be an issue of the degree of dysfunction; maybe the environment or heredity or combination thereof, that creates a homosexual orientation is not as damaging as the one that creates pedophilia, therefore one may be changeable and the other not.
Totally icky subject, but a very important one. Sure would be good to have a bit more insight.
Perhaps it's that people who actually act on pedophile urges (as opposed to those who feel those things, but supress them) are different from those who express homosexual urges in the current social climate. In other words, being homosexual is much less demonized (and in some circles seems to be encouraged) where pedophilia is seen by all but the smallest minority of people, as not only wrong, but criminal.
So, it could be that your sample in each group is very different.
I hope that makes sense.
susie