Why frightening? People want to record memories of things that are important to them. Seeing the pope is important to a lot of people.

Would you say the same about all the people at a Pop concert? People derive emotional value from their pictures and videos. Little computers-in-your-pocket just happen to make it easier.

Aside: We don't really know how many of those people in the pope-pic are sharing vs just recording for posterity -- the OP is primarily talking about the former

EDIT: Turns out the pics aren't really comparable. https://news.ycombinator.com/item?id=5492146