They are taught from birth that he is real, and that he loves you eternally, and gives you everything, so to question him in any way would be the ultimate slap in the face, and to add to that guilt, they are threatened with eternal suffering and anguish and torture, shit, that kept me christian as a kid
i will go to the grave knowing i met a living Savior. it is one thing i can never say otherwise. you ask me why i know He lives, He lives within my heart.
This is a spiritual question...Christ being real in our lives. It takes spirit to understand spiritual things. Jesus is real. He speaks through His word, He comforts, He cares, He is always there. It is not in a physical sense as you are suggesting (or so I think you are). It is within yourself. It is a relationship with the Creator.