I've noticed a trend among Christians who adopt the beliefs of evolutionists. They usually aren't solid on the doctrine of inerrancy in the first place. They have nagging doubts or a general sense of discomfort with the idea that the Bible is completely trustworthy in every possible way. Over time, they allow themselves to be deceived through the pseudo-science and propaganda presented by atheists and agnostics. Perhaps there is social pressure, and they don't want to look ridiculous. They may even say they are trying to remove any possible "scientific" hindrance to the Gospel.
Once evolution has been accepted, it becomes the unbreakable fulcrum under the logical lever that dislodges Biblical inerrancy from their minds once and for all. Rather than viewing Scripture as "incapable of being wrong," they come to see evolution as "incapable of being wrong." It's a tragic mistake and an example of misdirected faith. With inerrancy conveniently removed, they begin to view the Bible as a theologically authoritative book containing culturally influenced factual errors. They then live on the scraps of whatever theological truth they can squeeze out of a supposedly erroneous document, and stop engaging critically and Biblically with their own culture. The next step (or should I say slide) is a direct departure from clear Scriptural teachings and a willingness to apply all sorts of odd hermeneutics in a way that makes the Bible remarkably similar in its "spiritual" theological emphasis to their own culturally absorbed views. In this way, deceived souls take insolent authority over the Text rather than living under the authority of the Text (they then quickly point out how humble and flexible and teachable they are - and how arrogant those "rigid, orthodox, conservative" believers are for insisting on the utter veracity of the Word of God).
In time, they deny every core component of the Gospel and replace it with whatever philosophy is currently in style. That's a classic mark of liberalism. In the end, the term "Christian" becomes a mere descriptive shell, and it no longer characterizes their conduct or thought processes. Culturally derived ethics are then artificially "Christianized" and exalted above doctrinal Truth, and the fortress of indestructible unbelief is complete. Now to write books and make false disciples!
Not every Christian evolutionist follows this path all the way through, but I've seen it often enough to call it a definite trend. Have you seen it?