Those who mindlessly rail against memorization are using shallow and low level thinking skills! Memorization DEVELOPS the thinking ability and gives a person more to think about! Memorization, particularly of more important facts, is like giving a brick layer more bricks with which to build.
Memorization is encouraged for older people to prevent dementia. It builds self confidence in children. It gives debaters more ammunition. It actually develops the ability to think, because it practices thinking. It exercises the mind!
Constructivists maintain that repeating something memorized is a low level thinking skill and should therefore be avoided. They denigrate it by saying it is "regurgitation" of "mere" facts, as though it is vomiting worthless bits of data! They equate it with "old fashioned, traditional" teachers.
Bloom's taxonomy of thinking skills should be drawn as a pyramid, because "lower" level thinking skills form the foundation and basis of the higher level skills such as evaluation and should have more time spent developing them. How could one evaluate without having the facts?!
Another way of looking at it is that NONE of these skills should be considered lesser or lower. All are necessary. Considering the body, do we need the nose more than the feet, the shoulder more than the hand, or the eye more than the stomach? All parts of the body are important, and the eye cannot say it hath no need of the neck, to expand upon the holy writ.
Memorization of IMPORTANT facts is very valuable. Constructivists don't like to judge one fact as more important than another, but some facts are much more worth knowing. Knowing dates of certain historical events helps one tie happenings together, developing a better understanding of why certain things happened then and now. Memorizing the top ten song hits of a particular year probably won't develop anything worthwhile.
Some things are more worth knowing, even though some may not understand that. Truth is independent of opinions however. Some educators make themselves popular by encouraging the learning of things that are popular instead of things that are important. This lack of discrimination of facts shortchanges students. We NEED to memorize worthwhile facts in order to become wise.