Sports, online forums, student fraternities, social clubs of every variety, etc. There are many ways to get active in society that don't involve beliefs in higher beings.
Spirituality offers frameworks for dealing with, and often embracing, many of the questions for which there may never be a satisfactory answer.
Whether you believe the postulates of a religion or not, there a ton of higher-level lessons to be learned from those who do.
There are tons of higher level lessons to be learned from both religious and non-religious sources.
And even then, Christians murder more people in the US than anyone, per-capita or otherwise.