You may be confusing the theory of evolution with the ideas that Darwin had. Darwin had ideas that go beyond evolution, including speculations on the origin of life. Modern evolutionary theory, however, does not deal with the origin of life. (BTW, what makes you think the modern theory of evolution is absolutely identical to what Darwin wrote 150 years ago? Science doesn't work that way. Modifications are made to a theory as new evidence is found.)
This is really prevalent - creationists argue about what Darwin wrote or said rather than focusing on what the modern theory of evolution actually is.
I think this is due to creationists considering Darwin's Origin of Species a religious text that evolutionists follow just by faith the same way that creationists follow the bible just by faith. Rather than addressing science, they try to pit Darwin the man against God.