Would I to hear this case in court, I would have still found in favor of the teacher, but for a different reason.
Namely, that creationism is not a religion, nor is it found in any religion, nor is it a science. My argument would go as follows.
Science has a fixed set of rules, called the scientific method, that are not unlike the rules for say, the game of chess. If you follow the rules of science, you have done just that, conducted an experiment following the rules of science. An experiment that is reproducible by anyone, using the same rules.
If you play a game of chess, you must do so by its rules, or it is not a game of chess, even if it uses a chess board and chess pieces. Likewise, many people call many things “science”, that are not scientific, even in the sciences, because they do not follow the rules of science. This includes interpolation and extrapolation of scientific ideas outside of the scientific method.
Some of the parts of evolution are not truly scientific, but other parts are. Thus, criticisms of evolution are justifiable on grounds that it is not fully scientific, and only the scientific parts should be taught as science.
However, criticizing evolution with the creation of a pseudo-science, creationism, compounds the error. Creationism does not use the rules of science, so it is not “creation science”, and since it is the mandate of schools to teach science, creationism has no place in public schools.
Your premise is faulty. The Bible's book of Genesis contains an account of creationism, so it is most definitely found in a religion.
some religions accept evolution. some don’t.
(in fact, many Christians accept evolution,
whether you agree with them or not,
because they don’t take Genesis literally.
just as the 7 “days” of Daniel aren’t taken literally.
...just as they believe God didn’t stop the Sun for Joshua,
as it literally says,
but instead stopped the rotation of the Earth.)
i don’t believe that man causes Global Warming.
(in fact, i believe the Earth is cooling)
yet Public schools teach “AGW”.
i see no solution, other than giving ALL parents a voucher,
and allowing them to select a school, that teaches what the parent is comfortable with.
If you don’t look then you will not find...
101 Evidences for a Young Age of the Earth...And the Universe
http://creation.com/age-of-the-earth
Center for Scientific Creation - In the Beginning: Compelling Evidence for Creation and the Flood
http://www.creationscience.com/onlinebook/IntheBeginningTOC.html
Dinosaur Shocker - 68 million year old T Rex w/ red blood cells
http://www.smithsonianmag.com/science-nature/10021606.html#ixzz0VZChRzSL
New Chromosome Research Undermines Human-Chimp Similarity Claims
http://www.freerepublic.com/focus/f-news/2565348/posts
Science in the Bible
http://www.clarifyingchristianity.com/science.shtml
Testimonies of Scientists Who Believe the Bible
http://www.freerepublic.com/focus/f-chat/2761001/posts