Creationism is not "just a metaphor for evolution." It is a word which covers a wide range of beliefs, include those who argue that each species was the result of a specific act of divine creation.
("In Creationism, special creation is a theological doctrine which states that the universe and all life in it originated in its present form by unconditional fiat or divine decree." - https://en.wikipedia.org/wiki/Special_creation )
> The absence of evidence for evolution does not, by itself, prove creation, of course; nevertheless, special creation is clearly the only alternative to evolution.
How can special creation - one type of creationism - be both a "metaphor for evolution" and "the only alternative to evolution"?
Obviously it can't, which is why it's incorrect to summarize creationism as you did.
Progressive creationism is more accepting of evolution, in that it says "microevolution" occurs but "macroevolution" does not. Even this cannot be seen as a metaphor for evolution, because it rejects part of evolution.
("In Creationism, special creation is a theological doctrine which states that the universe and all life in it originated in its present form by unconditional fiat or divine decree." - https://en.wikipedia.org/wiki/Special_creation )
Take this quote from "The Vanishing Case for Evolution" by Henry Morris, http://www.icr.org/article/vanishing-case-for-evolution/ one of the founders of the Institute for Creation Research:
> The absence of evidence for evolution does not, by itself, prove creation, of course; nevertheless, special creation is clearly the only alternative to evolution.
How can special creation - one type of creationism - be both a "metaphor for evolution" and "the only alternative to evolution"?
Obviously it can't, which is why it's incorrect to summarize creationism as you did.
Progressive creationism is more accepting of evolution, in that it says "microevolution" occurs but "macroevolution" does not. Even this cannot be seen as a metaphor for evolution, because it rejects part of evolution.
Perhaps theistic evolution fits your description (https://en.wikipedia.org/wiki/Theistic_evolution ) but otherwise most types of creationism do not.