Because there has been renewed discussion of religion in mainstream media. There was a movie about the visions at Fatima. And it's a little more important than the death of rapper "Old Dirty B******," someone I'd never heard of.
Perceptions are a tricky thing. I find the Sister's death well covered via Google news it. I disagree with you and would not assume the Sister's death at a very old age death would be a front page headline.