In my personal opinion the judge took into consideration that RSB is not a direct menace to society (most probably will not harm anybody) and in lieu of this did not need a custodial sentence.
Probably the addiction/illness that he has needs to be addressed by an intensive professional supervised treatment course.
Hopefully he will have enough sense not to show up around the airport anymore and live out the rest of his time well away from anybody who knew him.
The irreversible damage that he did to himself was of his own doing and he will have to live with this for the rest of his life, but his actions to those that are also involved in this (child victims and the staff at ASW) as a result of his actions are inexcusable.