Do you mean OEC? Because I would agree. And I do think OECers can be Christians. After all, it's Christ and Him crucified. That said, it's not a consistent faith.
The main thing about a Christian believing in any part of evolution is that belief is opposed to the plainly written scriptures.
The one terrible result is once a young Christian gets to college, public or private, however much of it was taken there is magnified many fold per science course. A plague on the churches they grew up in is a wholesale departure of them from any religion. Few are prepared to defend themselves against the atheist community that prevails there. Students are forced to learn it well, now built in to every science field, through a massive abuse of the true science method. Evolution is now declared science, even though not meeting the requirements of science. Belief in it is enforced by professors, even many that intimidate Christians, and peer pressures that are highly negative. A Christian either lives with it all to graduate, or drops to the bottom of the class.
So I agree it's slightly possible for a Christian to believe in evolution and be known as a disciple of Jesus besides, but I know that is a major stumbling block for youth. If Genesis is at all discredited, a book upon which Judaism and much of the essentials of Christianity are founded, then the whole Bible becomes a target of scoffers. They are brainwashed in steps from grade school upwards, the intensity growing year by year. Schools have figured out how to avoid alarming parents until the students are adults, then they go for the spiritual kill.
It can be argued some were not really Christian before college, so were easy prey. I've met precious few parents who could balance truth against fiction at home, teaching children how to recognize false teaching. A few home-schooled children get that training, a big reason for parents to bite that bullet early on.