The problem is that the common usage of the terms "evoluion" and "Darwinism" are not confined to science. The terms have expanded to include the philisophical and even the theistic. For example, "Darwinism" can mean evolution by natural selection, sometimes mean what scientists call the "synthetic theory of evolution" (the union of genetic theory with natural selection theory), sometimes mean gradual evolution, and sometimes "Darwinism" means evolution itself. Sometimes "evolution" is used as a purely scientific idea, and other times it is confused with evolutionism, a naturalistic ideology that excludes the possibility of divine intervention. Also, even within the science of evolution there is a myriad of complexity and dissparate levels of proof (e.g.,inter and intra species evolution, etc.).
The truth is the neither the Intelligent Design pundits nor the "Evolutionists" are arguing science. It is, at its core, a philisophical debate.
"Leave Science to the Scientists and Religion to Theologians."
Leave atheism to the atheists.
Evolution is nothing but atheism in disguise.