We didn't invent creationism, we invented the THEORY of creationism. It is simply logical: the chance of human life being founded in a universe like ours is so microscopically small, it was probably the work of a creator, who used the processes of evolution, the Big Bang, and natural selection like tools. It all fits. What atheists have done to science is cut religion out of it, to answer your question. If you consider some religious theories, a lot more makes sense.