Can't deny at all!
These observations reveal our real reason behind fear. However, for each cause of fear, there might be more than one reasons behind it. For example, "afraid of dark" might mean fear of stumbling over stones, fear of confronting with ghosts, beasts, etc, and fear of not knowing the way.
So, probably we use one common cause to denote or imply a lot of hidden causes and implications! - Means we are being economical in our speech!
Heck, we are great managers by nature!