First of all the theory of evolution does not address the origin of life. Darwin’s book was called Origin of the Species, not origin of the universe. (And yes I’m aware it’s not the “Bible” of biology, as it were.)
Might want to brush up on your science there. Not going to lie, even Miss Frizzle would be dismayed at such a showing.
Secondly how does teaching biology promote evolution? Life forms mutate, that’s just observable reality. You can see it in diseases even!!! Does that mean reality promotes evolution?
Science is based in logic, don’t force lofty artsy ideals/interpretations into the STEM side of things. They don’t mix very well.
And thirdly, the alternative can be anything from aliens to an experience concocted by Buddha. You are aware that many atheists can also be found in religions such as Jainism or Buddhism, right? And some religions even go so far as to outright reject the concept of a creator God/goddess?
Life is more complicated than “evolution or God did it.”