Christianity is simple; it's meant to be accessible to everyone, regardless of era or culture. Joining the club is easy; being a member is hard - it's a life's work, and no one ever gets it perfect. If someone has "done a bad deed", it's not the religion's fault: it's the person's fault (see religion and violence). A true Christian is someone who has accepted the salvation offered by Christ via his death as the sacrificial lamb for our sins; messing up != returning the Gift, though one's Christian life, or lack thereof, may consist of returning it (the old "faith + good works = salvation" equation).