There probably is a "religiosity survey," someplace. However, in the case of evolution, one need only look at the derision with which Intelligent Design is treated, to understand that even the possibility of God is not acceptible to the "evolution mainstream." (I recognize that a lot of the derision is probably due to the taint of Biblical literalists having glommed on to the idea.)
I don't know if I buy that- I think the more likely reality is that, in today's PC environment, professors and teachers prefer to leave a contentious topic like God out of the classroom.
I can see your point, but I still think it's because it would not even occur to these folks to bring God into the discussion. If it did occur to them, though, I think their considerations of PC would be more directed to the response from other science people, rather than the ACLU.
The problem with ID is that there really is no way to apply the scientific method to it. I personally believe that God created the universe. However, that's an article of faith- there's no way for me to scientifically prove that. We shouldn't even try to prove the existence of God scientifically because God exists outside of our rules of science. All we can hope to do with science is explain how the rules created by God actually work when it comes to, for example, evolution.