Because of the overwhelming amount of evidence for it and total lack of evidence contradicting it.
Can you provide an example of some the evidence supported it?
I can do better, but need an indicator that you're worth the effort before I expend it. Demonstrate that you have actually read and understood everything on that little primer and I'll be happy to show you the way to some of the heavier material.
I might want you to know that I have read a book on this subject...
Regarding the horse fossil evolution:
The diagram on the wikipedia page has been disregarded by scientists for years. This is because the diagram is direct evolution, which they know is a myth. They have since then replaced it with a branching diagram that, although it branches off to extinct species of horse-like creatures. However, this diagram still shows a linear pattern that goes from Hyracotherumto Equus. this shows that the scientists cannot find a way to show HOW the modern horse evolved from Hyracotherum and they are instead clinging to previous beliefs that they know are not true.
Regarding Darwin's Finches:
There is only one mention of these birds in Darwin's logbook from his voyage aboard the Beagle and there is no mention of these whatsoever in The Origin of Species. A study in the 1970's showed that in a drought, the birds with larger beaks survived because they could eat larger nuts, this is a good supporter of natural selection,yes, but in the 1980's, the drought ended and the smaller-beaked birds came back. This is evolution in reverse. Because of this, a question arises: If this happened, then why hasn't the fossil record showed us that, after certain events, species had changed back to their previous state of living?
I can add more if you want. B)
Evolution is adaption [somewhat].
There is no "reverse evolution".
Evolution is not a pyramid, with organisms climbing up to get 'better'.
Do you see any evidence supporting creationism concretely, other than a book written by some cracked out book written by dudes living in the desert?
I mean, evolution isn't absolute by any means, but it's definitely more plausible than clay and rib people, talking snakes, and cursed apple trees. I mean...come on. Seriously. What evidence is there to suggest that snakes have or ever have had the intellectual capability to develop a complex spoken language, one that could be understood by humans no less? Where the ******** did Eden go after that story? It certainly isn't anywhere on earth, that's for sure.
Anyways, nothing is absolute, but creationism is just downright obnoxious in it's assumptions and violations of all the things we know of biology. Evolution at least has the benefit of probability and congruency with known knowledge. neutral