One of the best attested facts in all of science is the fact of evolution. There is still some debate over aspects of the theory of evolution, but thousands of researchers working over a period of 150 years have proven beyond all reasonable doubt the fact of evolution; it has occurred and is occurring. 
Creationism, the idea that a supernatural being has created all the individual species or types of living things, denies the truth of evolution; creationism, obviously, is anti-evolution. 
The fact and theory of evolution are among the greatest achievements of science, bringing together evidence from dozens of branches of science, such as botany, taxonomy, paleontology, geology, genetics, and many others. The theory of evolution provides a grand conceptual basis and organizational scheme for these sciences and for all of biology.
To be anti-evolution is to deny the validity not only of evolution, but of science itself, of its practice and its results. In short, to be anti-evolution is to be anti-science.
The sciences are arguably the greatest product of the Enlightenment, which was a resurgence of Western culture as it freed itself from the thousand-year suppression by the Christian Church. The scientific approach, applying reason to evidence rather than applying faith to scripture, brought every field of study, every subject of consideration, out of the Dark Ages, promoting a general blossoming.
To be anti-science is to be anti-Western. 
America is not simply an example Western nation, America was the first nation to be founded upon Enlightenment principles–that is, Western principles.
To be anti-Western is to be anti-American. 
But we can approach this issue from another direction. Anti-evolution activism is in fact an attempt to suppress the materialist and humanist world-view promoted by science in particular and secularism in general. This is merely one aspect of a program to impose a Christian theocracy on America, in place of the secular Constitution. This broader program is obviously anti-American.
I rest my case.
 Similarly, there is the indisputable fact of gravity and the associated theory of gravity, which is by no means settled.
 Creationism’s offspring, Intelligent Design, is simply the creationist wolf poorly disguised in sheepish clothing, pretending to be science.
 Orthodox Christianity, orthodox Judaism, and orthodox Islam are all anti-Western for the same reasons.
 Of course, most of the 60% of Americans who do not accept the fact of evolution do not recognize that they hold an anti-American position. And, since only an estimated 5% of Americans actually understand the general concepts of evolution, we have to attribute the lack of acceptance to ignorance rather than to malice.