Philosopher, Sage, Luminary and Professional Thinking Person

Actually, if you were paying attention, you’d discover that the observed fact of evolution is being taught as a fact, while the theory of evolution (that explains that fact) is taught as a theory.

The theory of gravity explains the observed fact of gravity, and yet nobody seems to mind that the theory is taught in school.

The germ theory of diseases explains the observed fact of diseases, and yet nobody seems to mind that the theory is taught in school.

And this is because, of course, when scientists use the word “theory” they don’t just mean a wild guess or an idea without any evidence to back it up. Instead:

In modern science, the term “theory” refers to scientific theories, a well-confirmed type of explanation of nature, made in a way consistent with scientific method, and fulfilling the criteria required by modern science. Such theories are described in such a way that scientific tests should be able to provide empirical support for, or empirically contradict (“falsify”) it. Scientific theories are the most reliable, rigorous, and comprehensive form of scientific knowledge, in contrast to more common uses of the word “theory” that imply that something is unproven or speculative (which is better characterized by the word hypothesis). Scientific theories are distinguished from hypotheses, which are individual empirically testable conjectures, and from scientific laws, which are descriptive accounts of how nature behaves under certain conditions.

— Theory – Wikipedia

I hope this helps clear things up a bit for you.