Also, I get what you're saying about worldly vs. unwordly. But there are plenty of things in science that are not of this world and that we cannot observe, but yet we believe in their existence. (ie - black holes) We hypothesize that they are there based on other evidence that points to the possibility of their existence. How is that different than creationists seeking to prove the existence of God, based on historical documentation of miracles, Jesus' death and resurrection, the great flood. All of these things point to evidence of the unworldly.
Oh, it's very, very different. In science, you first have a theory (that is likely to be based on some other evidence), then within that theory you make a prediction that is testable. In this situation, general relativity predicts that black holes can exist (providing a process for their production is a different discipline), and provides a number of very specific predictions as to the properties such black holes would have that we could possibly measure from Earth. Then we go out and look for astronomical objects with these specific properties.
The exact same thing is true of electrons, protons, neutrons, neutrinos, and the entire zoo of subatomic particles. Nobody has actually
seen any one of these things: we have a theoretical model that provides a physical explanation for the observations. If new observations showed that our old theories were incorrect, we might completely transform our descriptions of these objects.
Attempting to do the same with religion acts in complete reverse. The doctrine provides an explanation, and people modify how they view the physical evidence to try to fit within this explanation, instead of allowing the physical evidence to change what they think about how the world works.
Edit: It is worth noting that a change in our fundamental theories may change our descriptions of these objects, but it will never change the fact that they exist. There are, for example, objects which have all of the properties of black holes that we can measure, such as the supermassive black holes that exist at the center of galaxies. If a change in physics tells us that these aren't really black holes, but something else, this doesn't change the fact that these objects we currently think are black holes are really out there to be observed. It just changes what we consider them to be.
In a similar way, evolution is undeniable. The evidence that it has happened is incontrovertable (unless you want to believe in a deceptive God), the only questions remaining are the exact mechanisms.