This is really a question about the relationship between science and faith.
In my opinion what it comes down to is whether or not you take the Bible Literally.
The story of Adam and Eve is just that, in a sense its a story about how and why God created human beings and our relationship with him and each other.
Science says that all humans can be traced back to 5 pairs of men/women. This, on the surface, is contradictory to the single-parent story of adam and eve. However, the Bible is not a scientific text, so both can be true.
Perhaps there weren't really humans alive during the dinosaurs, but if you read the first account of creation, Humans were created AFTER animals... so really, there's not a whole of contradiction on the very basic beliefs.
The other reason is that teachers aren't really supposed to talk about faith/creationism in public schools.