What proof is there that evolution is not a RELIGION itself?
Umm, that proof would be the quite clear definition of the term "religion" which doesn't match the scientific theory of evolution. In my view, a more interesting question would be: Why do creationists have such a low regard for religion that they consider it an insult to call evolution a religion?
Webster's defines religion as follows:
a. Belief in and reverence for a supernatural power or powers regarded as creator and governor of the universe.
b. A personal or institutionalized system grounded in such belief and worship.
Evolution makes no claims about any supernatural powers, neither denying nor affirming them. Ergo, evolution is not a religion.
They don't pass the collection plate.