Alex, good points again.
But the alien experiment theory just pushes the issue of origins back a little further. Where did the aliens come from? Were they created or did life arise on their home planet without intervention?
About the teachers, it's very true, and many science teachers make a point of stating that Evolution is just a theory because they are creationists at heart.
The dichotomy of "facts" vs. "theories" in science is not all that relevant. The reasons why elements bond the way they do is theoretical, and subject to change with better info. The reason why electricity flows the way it does is theoretical, as well.
Facts are the observations of phenomena we see around us, scientific theories explain why those factual events have occurred and whether they'll occur again. Furthermore, science classes are about teaching students the current theories that will be relevant to them if they choose a career in science, as well as teaching them "the scientific method" that can be useful in nearly all careers.
Facts are for history classes, science deals with theories.