Looking at cultures across the world and throughout history, you'd be hard-pressed to find a single one that isn't characterized by religion. Even today, in our progressive, post-Enlightenment society, religion plays a major role in our social institutions and moral codes. Of course, its continued influence begs the question-at a societal level, is religion a force for harm or good?
Yes, religion is detrimental to society
The social institution critiqued by Karl Marx as "the opiate of the masses" is just as harmful as any literal drug, promoting tribalism and permitting atrocities in God's name.
Religion divides people
By creating "in-groups" of saints and "out-groups" of sinners, religion causes divisions within societies that have historically threatened to tear them apart.