Are politicians disproportionately pedophiles/hebephiles? In terms of 20th century+ politicians, I know of Bill Clinton, Ghandi, and Ho Chi Minh who probably banged underage girls.
People with no moral or practical restrictions on their behavior will always end up practicing the extremes.
These people believe people are just meat servants here for their use and no one is going to stop them. They don't care about anyone's suffering.
The ones who don't start out that way are most often easily brainwashed to do so because they only began as weak willed, self absorbed muppets who lack any shred of moral conviction. Of course loads of them are going to fuck anything that moves.
You can add Roman emperor Tiberius and several others to your list. I know you are focused on the 20th century but it isn't unique to our times.
Ordinary people are also pedophiles. They typically will be prosecuted at some point and ostracized, the sex offender public registry being a clear example of punishment beyond prison. The question clearly isn't why are there pedophiles but why there seems to be a multilayered criminal justice system that treats different classes differently. Of course again it's more than just the justice system, society as a whole has different standards for different demographics. Why is Trump considered a misogynist by many but Bill Clinton is never held accountable for his abuse of women? The answer of course is that the liberal establishment protects it's own. Not to mention that having money means the state is unable to use it's overwhelming resources to force plea bargaining or use other prosecutorial misconduct to badger criminals and non criminals into submission. If a person has billions they can literally "bankrupt" the justice department, at least in terms of resources. This means that pedophilia may be more evenly distributed among the various social economic classes than it appears because of the lower classes fear of prosecution or the lower classes feel compelled to conceal it more carefully. I don't think that any statistics you could find would be reliable because self reporting is out of the question.