Can you justify morality without religion? I'm a theist myself mind you, but it's often done in the following ways.
People form groups for survival. The purpose of a society or group of people is burden sharing, ie. if someone experiences a tragedy, the rest of the group can fulfill his or her role(s) either temporarily or indefinitely, with little to no or at least minimal negative impact on the overall survival of the group as a whole. The more burdens we remove from a group or society (the criminal minded, murderers, thieves) the less resulting pain, anguish, and just wasted time there is, thus benefiting the society and moving it forward if not for the simple reason there's more times to focus on work or leisure without worrying about/being weighed down by the negative emotions that result from said burdens.
Furthermore, the days of world wars have largely ended. So the lifeblood of the modern day economy is now trade, resources, services, etc. Say you have two lands, Pretoria and Esotropia. Pretoria has stricter laws, safer streets, and much less crime than Esotropia. Why would I want to live and work in Esotropia when I can do so in Pretoria? Show me a neighborhood or region whose streets are riddled with crime that people actually want to move in to that has a vibrant economy, and I'll show you a purple horse.