Perhaps you would like to explain where Dawkins does so. The weasel program - which is covered in only a few pages in The Blind Watchmaker - is intended only to show the advantage of what Dawkins calls “cumulative selection” over “single-step selection” (which is essentially random guessing). It is not billed as or intended to be a simulation of biological evolution and Dawkins says that it is not accurate as such.
(It is interesting that criticisms focus on the relatively unimportant weasel program and not on the biomorph program that occupies the bulk of that chapter - and is intended to be closer to biological evolution, though still not a simulation).