I think it's more of a deep seated psychological inferiority complex based around the person's sexual prowess. They feel powerful from wealth, and they don't want to feel weak when a woman notices their inexperienced behaviors or makes fun of their size. By choosing a young person, inexperience is what you're getting. Someone's first time they will have little knowledge of what is good/bad in a sexual engagement. That child becomes a toy for them to express their sexual desires without being self conscious of their actions.

At least that's from my armchair psychologist pov. There's definitely more study needed, but it seems like wealth often correlates to this type of behavior.