He did nothing in the wrong. He simply said that if you took Genesis literally than you will miss the greater picture and other things. There are many ways to look at texts, especially religious text. To say there is only one way to look at them (literal way for example) is foolish in the sense that you limit any possible understanding that can be derived from the text. Also, not all Christians take Genesis to be literal anyways, there are many who think it is metaphorical. In fact, one of my professors told my class once that if you actually look at the style of writing in Genesis (such as grammar and syntax) there is evidence to show that there were four different authors of Genesis. :/

He may have crossed the line by saying it was a "fairy tale" but the thing is, when he said it, it was after class to a single student. In such a personal scenario it is most likely he was only saying his personal view.

Anyways, it makes sense that the Bible would be used in a Western Civilization class seeing as how much it has impacted Western Civilization.

Also no theory of creation whether it be Creationism or Evolution are indeed facts, like said earlier they are merely theories. He did not even say Creationism was wrong, simply that the story of creation told in Genesis should not be taken so literally. After all, man was created twice in Genesis. First in chapter one (God creates man and woman in his image) then in chapter two with the story of Adam and Eve.