Inappropriate over-reaction to a storm in a teacup. The witch-hunt mentality probably arose as the result of a conservative American-style Christian upbringing that views all expression of sexuality as "evil", regardless of the consequences for the actors and any of their recipients.
People who download child porn are not necessarily the ones who act on it. It could have been a useful release for a guy with feelings he needed to contain in the real world. I am repulsed by people who indulge pornographic fantasies but it is their life, not mine. If they are doing no harm to others, or to themselves, then I have no right to use my repulsion to condemn or punish them. That is a moral maturational level that this Federal Agent has apparently not yet reached.
The acts of this School Principle are far less serious that the rampant active sex abuse of children by Catholic clergy, and the less frequent, but also egregious, sexual exploitation of parishioners by non-Catholic clergy.
In this particular case there appears to be no evidence that the legally tortured Principal did anything more than just look at electronic images. Unless such evidence has been repressed (and why would the media want to suppress such salacious material?) there did not seem to be any people harmed by what was
happening - until this self-righteous authoritarian started formal legal proceedings. It was =that= act that caused an avalanche of damage. It smashed friendships, broke up a marriage, deprived children of a father, caused irreparable damage to the mental well-being of everyone in that family, deprived a school of its Principle, and probably unnecessarily upset a lot of the kids at that school and their parents. If we look at the results, then this rigid FBI agent is the real criminal, He is the one causing all the harm.
In the higher stages of moral development people recognize that it is the consequences of actions that make them "moral" or "immoral". If the only thing harmed is the transgression of some asserted set of "absolute morals" on which there has never been anything close to a universal consensus, or the sensibilities of some cult-specific version of a supernatural being for which there is even less valid evidence, then we are looking at the operation of moral reasoning that is at the immature end of the normal moral maturational ladder.