The fact is that's nowhere near true. It's a completely ignorant claim. Not stupid, mind, but definitely ignorant. Which is O.K. You've probably never read Darwin's works. Most people haven't. Even most modern biologists haven't. But nevertheless the fact is that Darwin put forth numerous lines of argument for both natural selection (his theory of mechanism) and for common descent (the inference that evolution has indeed occurred and that diverse, and probably all, living things are related by ordinary biological reproduction).
With respect to the latter you ignore, just for instance, an entire chapter in the Origin where Darwin marshaled a series of arguments from the facts of biogeography (the geographical distributions of living organisms).
He was probably a Dummie.
You mean a "DUmmie"? No. Politically Darwin was a conservative (in modern terminology, although a "liberal" in 19th Century terminology). He belonged to and was a partisan of the (English version of) the party of Lincoln: The Whig party, which in America became the Republican party.
My goodness, stultis and stultorum right next to one another. That's got to be a neat little Latin lesson!
The Democrats are well on their way to becoming Whigs.