> So whose social interaction makes it absolute?

I'm sorry, I don't think that arbitrary and absolute are like black and white. By "not arbitrary" perhaps I should have said "slightly less arbitrary."

> Try and give a non-arbitrary example.

It's quite concrete if someone is arrested and imprisoned for molesting children. The laws used to justify the imprisonment may be arbitrary, but the consequences of those laws are not. The threat of imprisonment will dissuade most people from molesting children and make them reluctant to associate with those who do, much like this supposed morality.