Religious Market Share

Why do I find it so amusing to learn about the religious market share? What I mean by this is how different churches fight each other for the limited number of religious people. It really seems like they are in a state of natural selection. They fight each other, gain territory, diverge into two or more separate "species", etc. I guess it is most amusing since it is primarily one religious denomination making fun of another. This is amusing since it is nonsense vs nonsense and comforting since they are busy fighting amongst themselves to bother with us heretics.