The catholic church is filled with pedophiles. Why? Because it is an organization with too much power. People who wish to abuse power flock to this.
Hollywood exist solely for perpetuating the abuse of women and children. Why? Because we give them power and evil people will do whatever it takes to get this power.
School teachers? You can look at the stats yourself - school teachers are more likely to be child predators than an average person.
What makes you think that a politician, someone with potentially more power than any of the others listed, would not be a position that would attract evil people who wish to abuse that power?