The answer is easy. ID let's the "God people" get their foot in the door. It's nothing more complex than that.
LOL - what exactly are "God people"?
Put down the broad brush for a sec. Not all of us "God people" are ignorant about science. It is unfair to lump all Christians into the ID and/or young earth creation groups. Here is an exerpt from "Evolutionary Creation", by Dr. Denis O. Lamoureux, PhD biology and PhD theology.
Evolutionary creation claims the Father, Son and Holy Spirit created the universe and life through an evolutionary process. This position fully embraces both the religious beliefs of conservative Christianity and the scientific theories of cosmological, geological and biological evolution. It contends that God ordains and sustains the laws of nature, including the mechanisms of evolution. More specifically, evolution is 'teleological,' and features plan, purpose and promise. In particular, this view of origins asserts that humanity evolved from primate ancestors, and during this natural process the Image of God arose and sin entered the world. Evolutionary creationists experience God's presence and action in their lives. They contend that the Lord meets men and women in a personal relationship, which at times involves both dramatic and subtle miraculous signs and wonders...
... Within Protestant evangelical circles, evolutionary creation is held by a small but growing number of individuals educated in both science and Scripture. In particular, a majority of these Christians trained in the biological sciences accept this position. The leading evangelical evolutionary creationist today is Howard Van Till. He spent most of his career at Calvin College, an institution considered to be the leading evangelical college in the United States supporting this view of origins. Van Till claims that God created the world 'fully-gifted' from its inception so that all the universe and life would evolve without subsequent Divine interventions. Evolutionary creation best describes the official position of the Roman Catholic Church, though it is often referred to in this tradition as 'theistic evolution.' In 1996 Pope John Paul II made international headlines by claiming that "new knowledge leads to the recognition of the theory of evolution as more than a hypothesis..."
... Evolutionary creation recognizes that the relationship between science and Scripture is the key to developing a Christian view of origins. This position notes that the Church's past struggle to relate the Bible and Galileo's astronomy provides valuable lessons for believers today wrestling with the creation accounts and the evolutionary sciences. Conservative Christians accepting evolution as God's method of creation are inspired by the famed aphorism that arose during this 17th century controversy, "The intention of the Holy Spirit is to teach us how one goes to heaven and not how heaven goes." Rewritten for the 21st Church, evolutionary creationists encourage us to understand:
The purpose of the Bible is to teach us that God is the Creator, and not how the Father, Son and Holy Spirit created.