Cod - there was an 11 year old girl who came tot he school I taught at with a similar reputation. Male teachers were all spoken to about the risk and being very careful of the dangers they could find themselves in if alone with this child.
Not saying this is what happened here.
There is no excuse for having sex with a 10 year old and it should be punishable to the highest order.
But without knowing the full story it is difficult to know how that sentence was arrived at.
Presumably if others in the know feel it was lenient then the sentence will be appealed.