Somewhere along the line, people of religion have declared ownership of the Golden Rule. There is an often espoused belief by "people of god" that non-believers can't be compassionate, or empathetic, or thoughtful, etc., of your fellow man.
So I guess the "believers" are saying that without the threat of punishment in an afterlife, they are incapable of being moral, of being considerate, and, in short, treating others as they would be treated. This is the kind of trash that religious leaders (and followers) have been cramming down our throats since time immemorial.
Yet these same people of god, in many religions throughout history, have had no problem persecuting, torturing, and murdering people that didn't share their beliefs. Even today, many self avowed christians do not apply the same rules of kindness and consideration to those who don't believe as they do. Many believe that those who do not believe cannot be trusted, have no conscience, and should not have he same rights as believers have.
Why is it such a stretch to believe that people are inherently good and don't require a god to keep them well behaved. In fact, it frequently is religion that teaches intolerance, inequality and distrust. Differences in religous beliefs or lack thereof is and has long been the leading cause of wars, persecution, and discrimination.
Attaboy