Admittedly I don't know the reason you left, but from a 3rd person perspective it's how I see it.
What can 4srs do now that they couldn't do in Behe? They can run things the way they want. That's personal motivation if I've ever seen it. The most logic I can see is as follow: I want it this way, but I can't have it this way here, therefore I have to leave.