Childhood indoctrination is a big part of it. I have been told by my 8-year old niece that she'd like to save me from drowning in a lake of fire. She was genuinely scared for me. It's literal child abuse followed by Stockholm syndrome.
Your young niece sounds a lot like my elderly family. They're conscious that they "just can't let go" despite being very progressive and open to new ideas and they're aware of that.