Many of our statutes are designed to protect children from adults who wish to blur the boundaries. Some laws have been enacted to protect those in the workplace from having their work and their personal life forced together in a way that is improper. People in positions of power and authority are expected to behave in a manner which does not put those with less power in danger. And when there are no written laws, there are often unspoken boundaries. Friends do not betray friends.
Spouses remain true to each other.
Parents nurture offspring, and do not abuse their trust. Police officers protect and defend. Well, not always. Everyone does, at one time or another. We have lied to our children about what is important in life.