How are personal religious beliefs nauseating? If they were teaching creationism in the classroom, I could see it as a problem, but neither of these posters actually mentioned that was the case. I'm sure that in my 12 years of primary education science teachers, a bunch of them were creationists. I'd bet it was close to half of them even.
Creationism is not a religious belief. It's an attempt to co-opt both science and religion into a misguided hybrid of both. It's not content to rely on faith and so it seeks to "prove" the Biblical story as a physical fact, thus missing all the spiritual allegory of the Bible, and it does so by distorting and fabricating evidence to fit its predetermined conclusion, in complete opposition to how science works.
My biology teacher did say to the class that he considered evolution to be merely an unproven idea. That is not merely a personal belief, it is a categorical falsehood and a misrepresentation of a fundamental truth of biology. So yes, I'd say he was letting his belief undermine his teaching. It would be like a math teacher telling the class that the ratio of a circle's circumference to its diameter might or might not be pi.
But I don't want people to get the wrong idea about my high school, which overall is just about the best public high school in America. My 11th-grade physics teacher was actually a professor of physics, and he did a fantastic job. He administered this great test that asked really cleverly constructed and eclectic questions that challenged us to figure out how to solve them, do whatever research was necessary to obtain the information we needed (and this was pre-Internet), etc. It wasn't just teaching facts and figures, it was teaching how to think, how to research and solve problems and employ deductive reasoning. And it was teaching how knowledge from all sorts of different fields can be interrelated. If more science teachers administered tests like that, instead of the preprogrammed, standardized, fill-in-the-blank crap that usually passes for testing in schools, then America would be much stronger in the sciences, and maybe our movies would be too.