They aren't like that. Which means, of course, that you haven't been paying much attention.
The theory of evolution has been proven, twice over. The first of these proofs has been available for anyone to read for longer than any of us has been alive. I've read it. Have you?
If you have, it's clear you didn't understand it.
I'm not an atheist, by the way. I'm a lifelong Christian, raised in a missionary family. But there's no particular connection between atheism and the theory of evolution, and that, too, was noted in print long before we were born:
I see no good reason why the views given in this volume should shock the religious feelings of any one. It is satisfactory, as showing how transient such impressions are, to remember that the greatest discovery ever made by man, namely, the law of the attraction of gravity, was also attacked by Leibnitz, “as subversive of natural, and inferentially of revealed, religion.” A celebrated author and divine has written to me that “he has gradually learnt to see that it is just as noble a conception of the Deity to believe that He created a few original forms capable of self-development into other and needful forms, as to believe that He required a fresh act of creation to supply the voids caused by the action of His laws.”
-- Charles Darwin, "The Origin of Species"; sixth edition (1872)