Such theories reveal 3 unwritten presumptions by their founders.
1) A continuity of being. There is a tremendous assumption that all matter and life is simply a product of previous processes, thereby framing all scientific investigation into a evolutionistic structure.
2) The universe as infinite. Just as equally, the boundary conditions of the universe are also easily solved as a finite structure, no longer implying the origin of life as being evolved, but is just as easily manifest as a creation from outside those bounds. However, the presumption of an infinite universe frames the study to reach predetermined conclusions.
3) That there are many, many, many things we do not know, but one thing we do know with absolute certainty, is that the Bible just couldn’t possibly be true. Accordingly, we will attempt to justify any theory by man made logical constructs, provided we can contradict things which have been reported by other reputable men as having been revealed by God, as a rebellious display of our personal arrogance.
You are wrong.
The only "assumption" is that the supernatural does not exist. This is based on the absolute fact that there is no scientific evidence for the existence of the supernatural. Current science says that the universe is finite. Many religions including the Roman Catholic Church, the Anglicans, the Methodists, and certain Jewish sects, have stated that evolution is consistent with their beliefs.