With everything I've read on evolutionary theory, it's still full of holes.
Yet it's taught as science.
Why?
There are always gaps in a scientific theory. There are gaps in Germ Theory as well, but you don't see a serious effort to bring a God-based replacement for Germ Theory into the classroom.
Yet it's taught as science. Why?
Because it is a testable, disproveable theory that best explains the process of speciation and has withstood the test of time. Almost every serious biologist in the world, the Catholic Church, and the best minds of our time accept Evolution as the most likely way that life on Earth developed from simpler to more complex forms.