Penn State, Pedophilia, Sex, and Morality Questions

I have been saddened and sickened by the news today coming out of Penn State University about former Assistant Football Coach Jerry Sandusky and the allegations of his molestation of children over a fifteen year period.  It is disgusting and depraved, and I pray that Jesus would do a mighty healing the lives of the people affected.

What I find curious is the multitudes of reporters and commentators who are shouting about the moral responsibility of Penn State football coach Joe Paterno to report and ensure follow-up action about the information he received regarding Sandusky's actions.  As a Christian I believe that Paterno (or anyone for that matter) who knew about the behavior of Sandusky should have done everything they could to help the victims involved.  Pedophilia and molestation are shameful, sinful, evil actions and lusts.

However, for those people who are not Christians I have to ask, "Where does your moral guidebook come from?  Who gets to decide what is moral or immoral behavior?"  I have always wondered about this.  My standard of morality is what God tells me in Scripture is his standard.  But for those that don't take the Bible as the authoritative standard of their lives, what standard do you use to condemn pedophilia as an immoral sexual behavior?

I don't understand how people don't see the inconsistency of saying, "homosexuality, pornography, three-somes, fornication with random partners and other sexually deviant behavior is normal and OK, but pedophilia, polygamy, and bestiality are not OK."  Who gets to draw that line in the atheist world?