Questions about acupuncture

The theory of acupunture is based on the easthern religion taoisme caracterised by a holistic way of thinking. They claims that energy runs throught "meridians" and that you can treat disease by stimulating "meridians" with needles. Sickness is a result from disorder in energy running throug the "meridians".

A lot of people are influenced by pseudoscience like ying and yang, which also form the basis of acupuncture. Why do people beliewe in such pseudoscience?
Why is it popular believing in such nonsense?

The theory of "meridians" is not a theory based on scientific materials. It's an theory based on faith, new science is adjusted to the theory, the technichs have been used for thousand of years, the theory haven't changed. Can we use the old chinese theory together with a scientific explanation of acupuncture, side by side? Is there a scientific explanation? Can we use the chinese theory by itself?

Acupunture is used in Denmark by educated doctors. Is that a garantee, that acupuncture works? Or do they use alternative treatment based on faith instead of science? Why?