We don't live in fear of bacteria. We wash our hands, clean wounds, and do common sense stuff like that. In the same way primitive and ancient men and women didn't live in fear of demons, spirits, mad gods. They learned to live among them.
They had incantations, prayers and amulets to fend off the spirits, to keep them happy, to maintain a good balance between the living and dead. In Ancient Mediterranean countries one such amulet was the genitalia. Consider the following:
"In Latin, the word testis (hence testiculus, little testis) means both 'witness' and 'testicle,' while the Greek word for 'testament,' diatheke, literally means 'by the bag,' which is equivalent to 'by the scrotum' as suggested by the Latin testamentum (that is, 'testiculation'). All this is related to the fact that it was universal custom in the ancient East to pledge faith or swear testimony by touching or grasping one's own and/or another's genitals."Imagine, instead of setting one's palms on a Bible and swearing an oath, placing your hand on your crotch. Some customs change for the better.