This information is not surprising to me.
When you believe there is an afterlife, you are never forced to get comfortable with the idea of death. It takes a long time to deal with the topic of your own demise, perhaps even a lifetime.
This is reminiscent of a teenager who is learning to awkwardly define who they are. Over time, after trying many things and failing at some and succeeding at others, the kid turns into an adult. The path behind them, full of good and bad experiences, defines this person and shapes who they are as an adult.
The other word for this is ... maturity... Oddly enough, it is not just for kids. Maturity is a process that defines how you deal with any awkward or uncomfortable situation. You simply muddle your way through it, learn something and use that experience the next time you see the same situation. Over time, you get better at it. Eventually you look pretty polished, and if you're lucky, you'll even feel pretty polished.
Anything that seeks to insulate you from reality, prevents you from maturing. The end result will not be pretty when it comes to a terminal issue like death...