Why not?
Because she is basing her belief on a false assumption that billions upon billions of stars having 14 billion years will make possible many advanced inter-galactic civilizations.
What she doesn't understand is that there are limiting probabilities upon probabilities upon probabilities which vastly reduce the total number of suitable stars, within suitable regions of their galaxies, having suitable type solar systems with large gas giants in the outer belts, with earthlike planets in habitable regions, having the right axial tilt, right rotational speed, right iron core, right moon, right amount of water, and on and on.
And then there is the matter she hasn't considered of how in a sterile pre-biotic environment do chemicals randomly assemble to produce even the simplest of cells which are mindbogglingly complex?
She has considered none of that and is just going on blind faith.