Complex sentence: Unfortunately for Kimito, the school only considered him a candidate for this project because they thought that he was a homosexual with a muscle fetish, and therefore no threat to the innocent girls' chastity.
Split into simpler sentences: Unfortunately for Kimito, the school only considered him a candidate for this project because they thought that he was a homosexual with a muscle fetish. Therefore, the school concluded that Kimito is no threat to the innocent girls' chastity.