Secular people do good stuff not out of fear of divine punishment, but because they simply believe that it's what's best for the world (humanity.) That is a more VIRTUOUS reason for doing good than for just avoiding punishment (in "hell"), as well.
You mean they don't do it for these reasons?
Stage one (obedience and punishment driven), individuals focus on the direct consequences of their actions on themselves
Stage two (self-interest driven) expresses the "what's in it for me" position, in which right behavior is defined by whatever the individual believes to be in their best interest but understood in a narrow way which does not consider one's reputation or relationships to groups of people
Stage three (good intentions as determined by social consensus), the self enters society by conforming to social standards. Individuals are receptive to approval or disapproval from others as it reflects society's views.
Stage four (authority and social order obedience driven), it is important to obey laws, dictums, and social conventions because of their importance in maintaining a functioning society.
Stage five (social contract driven), the world is viewed as holding different opinions, rights, and values.
Stage six (universal ethical principles driven), moral reasoning is based on abstract reasoning using universal ethical principles.